| 单词 | self-fertilised |
| 例句 | Many hermaphrodite plants are, as first shewn by C. K. Sprengel, dichogamous; that is, their male and female organs are not ready at the same time, so that they cannot be self-fertilised. The Descent of Man and Selection in Relation to Sex, Vol. I 2011-01-17T03:00:49.523Z But this inequality did not continue, for, when the crossed plants were four and a half inches high, the self-fertilised were three inches; and they retained the same relative difference till their growth was complete. The Variation of Animals and Plants Under Domestication, Volume II (of 2) Continued close inbreeding, on the contrary, eventually leads to deterioration, though, as in many self-fertilised plants, a considerable number of generations may elapse before it shows itself in any marked degree. Mendelism Third Edition Besides these pairs of competitors, others were planted in beds, so that the descendants of the crossed and self-fertilised flowers might compete. Life of Charles Darwin We are reminded by this latter fact of the extraordinary case of Hippeastrum, Lobelia, &c, which seeded much more freely when fertilised with the pollen of distinct species, than when self-fertilised with their own pollen. On the Origin of Species by Means of Natural Selection or the Preservation of Favoured Races in the Struggle for Life. (2nd edition) Now Henslow, in his "Floral Structures,"19 adopts the same theory for all the wind-fertilised or self-fertilised flowers, and he tells me that he is alone in the view. Alfred Russel Wallace: Letters and Reminiscences, Vol. 2 The experiment was repeated in the two following generations with plants raised from the self-fertilised and crossed plants, treated in exactly the same manner, and with nearly the same result. The Variation of Animals and Plants Under Domestication, Volume II (of 2) Nor is the problem one that concerns self-fertilised plants only. Mendelism Third Edition But, as Darwin remarks, profuse expenditure is nothing unusual in nature, and it appears to be more profitable for a plant to yield a few cross-fertilised than many self-fertilised seeds.- Life of Charles Darwin Most of these, however, may be insect fertilised occasionally, and may, therefore, come under the rule that no species are perpetually self-fertilised. Darwinism (1889) It often occurred to me that it would be advisable to try whether seedlings from cross-fertilised flowers were in any way superior to those from self-fertilised flowers. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Several long-styled and short- styled plants were protected from the access of insects, and must have been spontaneously self-fertilised. The Different Forms of Flowers on Plants of the Same Species In many of these experiments, the crossed plants yielded much more seed than the self-fertilised plants; and I have never seen the reversed case. The Variation of Animals and Plants under Domestication — Volume 2 An equal number of crossed and self-fertilised capsules contained seed by weight in the proportion of 100 to 71. More Letters of Charles Darwin — Volume 2 An immense variety of plants are habitually self-fertilised, and their numbers probably far exceed those which are habitually cross-fertilised by insects. Darwinism (1889) Nevertheless, the self-fertilised seedlings were plainly inferior in height and vigour to the crossed. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Twenty-three spontaneously self-fertilised capsules from this form contained, on an average, 19.2 seeds. The Different Forms of Flowers on Plants of the Same Species The seedlings were at first equal in height; but when the young crossed plants were half an inch, the self-fertilised plants were only a quarter of an inch high. The Variation of Animals and Plants under Domestication — Volume 2 Nevertheless, the self-fertilised flowers produced an abundance of seed. More Letters of Charles Darwin — Volume 2 Sprengel, many hermaphrodite plants are dichogamous; that is, their male and female organs are not ready at the same time, so that they cannot be self-fertilised. The Descent of Man My attention was now thoroughly aroused, for I could hardly doubt that the difference between the two beds was due to the one set being the offspring of crossed, and the other of self-fertilised flowers. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The self-fertilised capsules also contained seeds, as compared with capsules from flowers fertilised with pollen from a distinct plant of the same form, in the ratio of 72 to 100. The Different Forms of Flowers on Plants of the Same Species Some self-fertilised capsules of a Maxillaria were in a similar state. The Variation of Animals and Plants under Domestication — Volume 2 I am going steadily on with my experiments on the comparative growth of crossed and self-fertilised plants, and am now coming to some very curious anomalies and some interesting results. More Letters of Charles Darwin — Volume 2 With respect to the cross-fertilisation of two distinct seedling plants, it has been ascertained that the offspring thus raised inherit much more vigorous constitutions and generally are more prolific than seedlings from self-fertilised parents. Life and Letters of Charles Darwin — Volume 2 The crossed and self-fertilised seeds thus produced were sown on opposite sides of the same pots, and treated in all respects alike; and the plants when fully grown were measured and compared. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Thirteen capsules spontaneously self-fertilised yielded an average of 53.2 seeds, with the astonishing maximum in one of 97 seeds. The Different Forms of Flowers on Plants of the Same Species The seeds were germinated on moist sand; two seedlings of the same age, one from a cross and the other from a self-fertilised flower, were selected and planted on opposite sides of the same pot. Darwin and Modern Science I believe the cause of the many vars. not crossing is that under our climate the flowers are self-fertilised at an early period, before the corolla is fully expanded. More Letters of Charles Darwin — Volume 2 We are reminded by this latter fact of the extraordinary case of Hippeastrum, Lobelia, etc., which seeded much more freely when fertilised with the pollen of distinct species, than when self-fertilised with their own pollen. On the Origin of Species By Means of Natural Selection, or, the Preservation of Favoured Races in the Struggle for Life For our purpose, however, of the comparison of the crossed and self-fertilised plants, their absolute height signifies little. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The equal-styled resembled in all respects those previously described; and eight of their capsules spontaneously self-fertilised contained on an average 44.4 seeds, with a maximum of 61 and a minimum of 23. The Different Forms of Flowers on Plants of the Same Species This results from the superiority of plants crossed in this manner over self-fertilised plants. Darwin and Modern Science I am now busy in drawing up an account of ten years' experiments in the growth and fertility of plants raised from crossed and self-fertilised flowers. More Letters of Charles Darwin — Volume 2 Combining these two elements, namely, the number of seed-bearing heads and the weight of seeds in each head, the productiveness of the crossed to the self-fertilised plants was as 100 to 75. Effects of Cross and Self Fertilisation in the Vegetable Kingdom As only a moderate number of crossed and self-fertilised plants were measured, it was of great importance to me to learn how far the averages were trustworthy. Effects of Cross and Self Fertilisation in the Vegetable Kingdom This average would be rather low for a long-styled plant artificially fertilised with its own pollen, but is high for one spontaneously self-fertilised. The Different Forms of Flowers on Plants of the Same Species But he had no doubt that in favourable circumstances self-fertilised plants were able to persist for several generations without crossing. Darwin and Modern Science You suggest the comparison of the growth of plants produced from self-fertilised and crossed seeds. More Letters of Charles Darwin — Volume 2 Many of the self-fertilised seedlings suffered greatly, and a much larger number of them perished than of the crossed. Effects of Cross and Self Fertilisation in the Vegetable Kingdom If so, and only on that condition, it would follow that when all the measurements, either of the crossed or the self-fertilised plants, were combined into a single series, that series would be statistically regular. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Hence the short-styled form of the cowslip, when self-fertilised, does not transmit the same form nearly so truly as does that of P. Sinensis. The Different Forms of Flowers on Plants of the Same Species In the autumn the surviving self-fertilised plants were plainly less well-grown than the crossed plants. Effects of Cross and Self Fertilisation in the Vegetable Kingdom I raised, however, a few seedlings of both lots, and the self-fertilised rather exceeded the crossed plants in height. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Four out of twelve capsules, spontaneously self-fertilised at the same time, were found to contain no good seeds; and the remaining eight contained on an average 6.6 seeds per capsule. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The self-fertilised plants, whether originally descended from one or two mother-plants, were thus in each generation as closely interbred as was possible; and I could not have improved on my plan. Effects of Cross and Self Fertilisation in the Vegetable Kingdom I raised twenty plants from self-fertilised seed sent me by Mr. Scott; and they all produced red flowers, varying slightly in tint. The Different Forms of Flowers on Plants of the Same Species But it should be observed that later in the season the same plants produced under a net plenty of very fine spontaneously self-fertilised capsules. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The fifteen crossed plants here average 21.91 inches, and the fifteen self-fertilised plants 19.54 inches in height, or as 100 to 89. Effects of Cross and Self Fertilisation in the Vegetable Kingdom These plants did not differ in fertility, as far as could be judged by the number of capsules produced, for there were seventy-five on the crossed side and seventy-four on the self-fertilised side. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Nevertheless, it is highly probable that self-fertilised seedlings have sometimes by this means got included amongst the crossed seedlings. Effects of Cross and Self Fertilisation in the Vegetable Kingdom As bearing on inheritance, it may be added that 72 seedlings were raised from one of the red-flowered, strictly equal-styled, self-fertilised plants descended from the similarly characterised Edinburgh plant. The Different Forms of Flowers on Plants of the Same Species This plant is remarkable from the crossed seedlings not exceeding in height or vigour the self-fertilised. Effects of Cross and Self Fertilisation in the Vegetable Kingdom We have therefore for the weights of the three lots of plants the following ratios:— The English-crossed to the self-fertilised plants, as 100 to 118. Effects of Cross and Self Fertilisation in the Vegetable Kingdom We thus see that in weight, as in height, the self-fertilised plants had a decided advantage over the English-crossed and intercrossed plants. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Summary on the growth, vigour, and fertility of the successive crossed and self-fertilised generations. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Thirteen capsules from self-fertilised perfect flowers gave an average of 62 seeds, with a maximum of 135. The Different Forms of Flowers on Plants of the Same Species The English-crossed plants, though so superior in productiveness, were, as we have seen, decidedly inferior in height and weight to the self-fertilised, and only equal to, or hardly superior to, the intercrossed plants. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Seeds from the flowers spontaneously self-fertilised under the net, and from flowers naturally crossed by the bees, were sown on opposite sides of five large pots. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The same number of plants of crossed and self-fertilised parentage were measured up to the summits of their flower-stems, with the result given in Table 4/35. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Small amount of pollen in the anthers of the self-fertilised plants of the later generations, and the sterility of their first-produced flowers. Effects of Cross and Self Fertilisation in the Vegetable Kingdom From the perfect flowers of this latter species covered with a net eleven spontaneously self-fertilised capsules were produced, and these yielded on an average 3.45 seeds. The Different Forms of Flowers on Plants of the Same Species The average height of the twenty-four crossed plants is here 17.17 inches, and that of the same number of self-fertilised plants 14.61; or as 100 to 85. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Of the crossed plants all but five flowered, whilst several of the self-fertilised did not do so. Effects of Cross and Self Fertilisation in the Vegetable Kingdom It is a singular fact that the tallest plant in the two rows, was one of the self-fertilised. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Uniform colour of the flowers produced by the self-fertilised plants. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Therefore the long-styled plants yielded nearly 24 times as many spontaneously self-fertilised seeds as did the same number of short-styled plants. The Different Forms of Flowers on Plants of the Same Species On the other hand, they exceeded the self-fertilised in height in a slightly greater degree. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The average height of the nineteen crossed plants is here 27.48, and that of the nineteen self-fertilised 22.55 inches; or as 100 to 82. Effects of Cross and Self Fertilisation in the Vegetable Kingdom All these plants were cut down in the early autumn and weighed: the crossed weighed 11.5 ounces, and the self-fertilised 7.75 ounces, or as 100 to 67. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The self-fertilised plant in Pot 1, which ultimately reached the unusual height of 80 4/8 inches, was for a long time taller than the opposed crossed plant, though at last beaten by it. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Character of the offspring from oxlips artificially self-fertilised and cross- fertilised in a state of nature. The Different Forms of Flowers on Plants of the Same Species We here have the anomalous result of the self-fertilised plants being a little taller than the crossed; of which fact I can offer no explanation. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The average height of the twenty crossed plants is here 29.98, and that of the twenty self-fertilised 27.71 inches; or as 100 to 92. Effects of Cross and Self Fertilisation in the Vegetable Kingdom They were first measured when about a third of their full size, and the crossed plants then averaged 3.87 inches, and the self-fertilised only 2.00 inches in height; or as 100 to 52. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Many of these lighter self-fertilised seeds placed on damp sand germinated before the crossed; thus thirty-six of the former germinated whilst only thirteen of the latter or crossed seeds germinated. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Hence we may infer that seedlings from self-fertilised oxlips would hardly be able to exist in a state of nature. The Different Forms of Flowers on Plants of the Same Species In four out of the five pots, a crossed plant flowered before any one of the self-fertilised; as likewise occurred with the pair raised during the previous year. Effects of Cross and Self Fertilisation in the Vegetable Kingdom By the early part of the summer of 1870 the crossed plants in all the five clumps had grown and spread so much more than the self-fertilised, that any comparison between them was superfluous. Effects of Cross and Self Fertilisation in the Vegetable Kingdom All the self-fertilised were now dead, with the exception of a single branch on one plant, which bore on its summit a minute rosette of leaves about as large as a pea. Effects of Cross and Self Fertilisation in the Vegetable Kingdom By whatever method the fertility of these plants is compared, the crossed are more fertile than the self-fertilised plants. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The belief that the flowers of many plants are fertilised in the bud, that is, are perpetually self-fertilised, is a most effectual bar to understanding their real structure. The Different Forms of Flowers on Plants of the Same Species So that the self-fertilised plants, besides their inferiority in other respects, were more tender. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Another experiment was now tried for the sake of ascertaining how far the superiority of the crossed plants, or to speak more correctly, the inferiority of the self-fertilised plants, would be transmitted to their offspring. Effects of Cross and Self Fertilisation in the Vegetable Kingdom We here see a considerable difference in height between the two sets, though very far from equalling that in the previous trials between the offspring from crossed and self-fertilised flowers. Effects of Cross and Self Fertilisation in the Vegetable Kingdom I thought that the advantage thus given to the self-fertilised seedlings would have been so great that they would never have been beaten by the crossed ones. Effects of Cross and Self Fertilisation in the Vegetable Kingdom These proved to be three mid-styled and one long-styled; but from so small a number we can hardly judge of the tendency in mid-styled plants when self-fertilised to reproduce the same form. The Different Forms of Flowers on Plants of the Same Species The average height of the four crossed plants is 14.25, and that of the four self-fertilised plants 14.31; or as 100 to 100.4; so that they were in fact of equal height. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Thirty-two other flowers on the same branch produced twenty-eight spontaneously self-fertilised capsules, containing on an average 17.2 seeds, with a maximum in one of thirty-six seeds. Effects of Cross and Self Fertilisation in the Vegetable Kingdom At the later period the three tallest crossed plants still exceeded considerably in height the three tallest self-fertilised, but not in quite so great a degree as before. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The seedlings came up, but all the self-fertilised ones soon died excepting one, which never twined and grew to a height of only 4 inches. Effects of Cross and Self Fertilisation in the Vegetable Kingdom For instance, thirty- four capsules produced by the illegitimate grandchildren of a long-styled plant, spontaneously self-fertilised, contained on an average only 9.1 seeds, with a maximum of 46. The Different Forms of Flowers on Plants of the Same Species So that the crossed plants were very much more productive than the self-fertilised. Effects of Cross and Self Fertilisation in the Vegetable Kingdom I had previously selected a medium-sized capsule from each lot, and counted the seeds in both; the crossed one contained 284, and the self-fertilised one 126 seeds; or as 100 to 44. Effects of Cross and Self Fertilisation in the Vegetable Kingdom A large majority of the spontaneously self-fertilised capsules produced by several plants contained no seeds, or only a single one. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The average height of the six crossed plants is 82.54 inches, and that of the six self-fertilised plants 62.33 inches, or as 100 to 75. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The fifth and last plant was decidedly more fertile; for 42 self-fertilised flowers yielded 11 capsules. The Different Forms of Flowers on Plants of the Same Species Out of a large number of plants, four of the crossed ones flowered before any one of the self-fertilised plants. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Both the crossed and self-fertilised plants, from having grown much crowded in the two beds, produced less fine capsules and fewer seeds than did their parents. Effects of Cross and Self Fertilisation in the Vegetable Kingdom From the first the crossed seedlings appeared the finest, and when they were on an average, by estimation, 5 inches high, the self-fertilised plants were only 4 inches. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The average height of the six crossed plants is here 87.5, and of the six self-fertilised plants 63.16, or as 100 to 72. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Secondly, nine capsules from another equal-styled plant, which had not been protected from insects, but probably was self-fertilised, gave an average of 45.2 seeds, with a maximum of 58. The Different Forms of Flowers on Plants of the Same Species On the other hand, the eight self-fertilised plants produced no less than thirty-six capsules, of which I examined twenty-five, and, with the exception of three, all contained seeds, averaging 10.63 seeds per capsule. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Twenty flowers on the self-fertilised plants of the last or third generation, in Table 4/46, were fertilised with their own pollen, but taken from other flowers on the same plants. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The self-fertilised plants had a decidedly less vigorous appearance than the plants of the other two lots, their leaves being smaller and narrower. Effects of Cross and Self Fertilisation in the Vegetable Kingdom This large difference was chiefly due to most of the plants, especially the self-fertilised ones, having become unhealthy towards the close of their growth, and they were severely attacked by aphides. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The female form, therefore, is very much more fertile than the hermaphrodite, as in the two last cases; but the hermaphrodite was necessarily self-fertilised, and this probably diminished its fertility. The Different Forms of Flowers on Plants of the Same Species In only one pot did a self-fertilised plant flower before one of the two kinds of crossed plants, between which there was no marked difference in the period of flowering. Effects of Cross and Self Fertilisation in the Vegetable Kingdom So that in height we have the following ratios:— The London-crossed to the self-fertilised as 100 to 81. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The flowers produced by the self-fertilised plants of the last or fourth generation were as uniform in tint as those of a wild species, being of a pale pink or rose colour. Effects of Cross and Self Fertilisation in the Vegetable Kingdom I was so much surprised at this case that I saved the self-fertilised seeds of this plant, which I will call the "Hero," and experimented on its descendants, as will hereafter be described. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Such flowers are therefore invariably self-fertilised; yet they produce an abundance of seed. The Different Forms of Flowers on Plants of the Same Species Many flowers on this Hibiscus were crossed with pollen from a distinct plant, and many others were self-fertilised. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Here we have the unusual case of self-fertilised plants exceeding the crossed in height; but only four pairs were measured, and these did not grow well or equally. Effects of Cross and Self Fertilisation in the Vegetable Kingdom In one pot the quasi-crossed plant was very soon and ever afterwards taller and finer than the self-fertilised. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Besides the plants included in Table 2/7, nine crossed and nine self-fertilised plants of the same lot were raised in two other pots, 4 and 5. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Therefore the capsules from the cleistogamic flowers contained fewer seeds than those from perfect flowers when cross-fertilised, and slightly more than those from perfect flowers self-fertilised. The Different Forms of Flowers on Plants of the Same Species The self-fertilised seeds germinated rather before the others; but as soon as I got equal pairs they were planted on the opposite sides of four pots. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The crossed plants now showed their superiority in another way, for only one out of the seven was killed by the operation, whilst three of the self-fertilised plants never recovered. Effects of Cross and Self Fertilisation in the Vegetable Kingdom In three of the pots the crossed plants flowered first, but in the fourth at the same time with the self-fertilised. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The average height of the eight crossed plants is here 113.25 inches, and that of the self-fertilised plants 96.65, or as 100 to 85. Effects of Cross and Self Fertilisation in the Vegetable Kingdom When grown to a considerable height the eight tallest crossed plants averaged 44.43, and the eight tallest self-fertilised plants 37.34 inches, or as 100 to 84. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The crossed plants yielded 243, whilst the same number of self-fertilised plants yielded only 155 seeds, or as 100 to 64. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Seedlings were raised in five pots from the above seeds, and when the crossed were about 3 inches in height they showed a slight advantage over the self-fertilised. Effects of Cross and Self Fertilisation in the Vegetable Kingdom In all the pots, excepting 4, a crossed plant flowered before any one of the self-fertilised plants. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Nevertheless two of the self-fertilised plants, as may be seen in Table 2/9, were still higher than their crossed opponents. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Nine seeds were saved from flowers spontaneously self-fertilised under a net, on the same plant which yielded the two crossed seeds. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The second crossed seed was sown in like manner with two self-fertilised seeds on the opposite side; these latter also came up about a day before the crossed one. Effects of Cross and Self Fertilisation in the Vegetable Kingdom In both pots, therefore, the crossed seedlings from germinating later, were at first completely beaten by the self-fertilised; nevertheless, this state of things was afterwards completely reversed. Effects of Cross and Self Fertilisation in the Vegetable Kingdom A few flowers on the one crossed plant were crossed with pollen from one of the self-fertilised plants, for I had no other crossed plant from which to obtain pollen. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The earlier flowers produced by these self-fertilised plants did not set any capsules, and their anthers contained only a small amount of pollen; but to this subject I shall return. Effects of Cross and Self Fertilisation in the Vegetable Kingdom One of the self-fertilised plants having been covered by a net produced plenty of spontaneously self-fertilised pods. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The crossed plants flowered before the self-fertilised in both pots. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Seeds from flowers spontaneously self-fertilised under a net were at the same time saved from the same mother-plant, the Painted Lady. Effects of Cross and Self Fertilisation in the Vegetable Kingdom In Pot 2 the other crossed seed was planted two days before a self-fertilised one; so that here the crossed seedling had a considerable advantage over the self-fertilised one. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The self-fertilised plants showed no sign of inheriting the precocious growth of their parents; this having been due, as it would appear, to the abnormal state of the seeds from the unhealthiness of their parents. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Nevertheless I allowed it to remain, and so great was its constitutional vigour that it ultimately beat its uninjured self-fertilised rival. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Many of the self-fertilised peas just referred to germinated on sand before any of the crossed ones, and were rejected. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The average height of the six crossed plants is here 62.91, and that of the six self-fertilised 55.31 inches; or as 100 to 88. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The average height of the seven self-fertilised plants, the offspring of crossed plants, is 71.57, and that of the seven self-fertilised plants, the offspring of self-fertilised plants, is 64.57; or as 100 to 90. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Therefore an equal number of the crossed and self-fertilised plants would have produced capsules in the proportion of about 182 to 47, or as 100 to 26. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The self-fertilised plants from the self-fertilised produced rather more pods—namely, thirty-six—than the self-fertilised plants from the crossed, for these produced only thirty-one pods. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The crossed plants also transmit their superiority in height and vigour to their self-fertilised offspring. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The average height of the four crossed plants is here 34.62, and that of the four self-fertilised plants 39.68, or as 100 to 115. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Ninety-three pods spontaneously self-fertilised on a large bush which had been covered up, but had been much agitated by the wind, contained an average of 2.93 seeds. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The self-fertilised plants, if well nourished, would almost certainly, in a few more generations, have produced double flowers, for they had already become in some degree sterile. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The crossed seeds compared with an equal number of the spontaneously self-fertilised seeds were heavier, in the ratio of 100 to 88. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The six crossed plants here average 2.91, and the six self-fertilised 1.33 inches in height; so that the former were more than twice as high as the latter, or as 100 to 46. Effects of Cross and Self Fertilisation in the Vegetable Kingdom So that the mean height of the two crossed plants was 19.81, and that of the two self-fertilised 17.37 inches; or as 100 to 88. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The crossed seedlings have an enormous advantage over the self-fertilised when grown together in close competition. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Looking to each pair, it may be seen that only thirteen of the crossed plants, whilst eighteen of the self-fertilised plants exceed their opponents. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The seeds after germinating on sand were planted in three pots, but all the self-fertilised plants died in one of them. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The crossed plants altogether produced 105 and the self-fertilised plants 63 capsules; or as 100 to 60. Effects of Cross and Self Fertilisation in the Vegetable Kingdom In both pots a self-fertilised plant flowered before any one of the crossed plants. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Some flowers were crossed and self-fertilised in the usual manner during two seasons; but as I reared on the first occasion only two pairs, the results are given together. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The twenty-seven crossed plants weighed 16 1/2 ounces, and the twenty-seven self-fertilised plants 20 1/2 ounces; and this gives a ratio of 100 to 124. Effects of Cross and Self Fertilisation in the Vegetable Kingdom On both occasions the crossed capsules contained slightly more seeds than the self-fertilised. Effects of Cross and Self Fertilisation in the Vegetable Kingdom But the plants from some cause never grew well, and finally became so unhealthy that only three crossed and three self-fertilised plants survived to set any capsules, and these were few in number. Effects of Cross and Self Fertilisation in the Vegetable Kingdom A plant of the common parsley was covered by a net, and it apparently produced as many and as fine spontaneously self-fertilised fruits or seeds as the adjoining uncovered plants. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The crossed and self-fertilised plants raised from these seeds were measured before they were in full flower, as in Table 5/65. Effects of Cross and Self Fertilisation in the Vegetable Kingdom A self-fertilised plant of the same parentage as those in Table 2/12 had been raised in a separate pot for a distinct purpose; and it proved partially sterile, the anthers containing very little pollen. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Only one crossed and one self-fertilised plant were raised in Pot 1, and their measurements are given in Table 5/66. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The flowers on this one self-fertilised plant were again self-fertilised under a net, not with pollen from the same floret, but from other florets on the same head. Effects of Cross and Self Fertilisation in the Vegetable Kingdom In Pot 3 one of the self-fertilised plants died before flowering, as has occurred in so many other cases. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The average height of the seven crossed plants is 19.43, and that of the six self-fertilised plants 16 inches; or as 100 to 82. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Several flowers on this plant were crossed with the little pollen which could be obtained from the other flowers on the same plant; and other flowers were self-fertilised. Effects of Cross and Self Fertilisation in the Vegetable Kingdom It appears that this plant is capable of producing a large number of self-fertilised capsules owing to the petals closing at night, as well as during cold weather. Effects of Cross and Self Fertilisation in the Vegetable Kingdom A capsule was obtained by crossing a flower of L. ramosa with pollen from another plant, and two other capsules from artificially self-fertilised flowers. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Some flowers on the crossed plants were again crossed, four capsules being thus obtained; and some flowers on the self-fertilised plants were again self-fertilised, seven capsules being thus obtained. Effects of Cross and Self Fertilisation in the Vegetable Kingdom So that the flowers on the crossed plants again crossed were much more fertile than those on the self-fertilised plants again self-fertilised. Effects of Cross and Self Fertilisation in the Vegetable Kingdom From the seeds thus produced four crossed and four self-fertilised plants were raised, which were planted in the usual manner on the opposite sides of two pots. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The above two lots of seeds were placed on damp sand, and many of the crossed seeds germinated, as on the last occasion, before the self-fertilised, and were rejected. Effects of Cross and Self Fertilisation in the Vegetable Kingdom In this latter pot, when the crossed averaged 5 inches in height, the self-fertilised were about 4 inches; nor did they look nearly such fine plants. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The average height of the three tallest crossed plants is here 23.33, and that of the tallest self-fertilised 19 inches; or as 100 to 81. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Besides this difference in height, the crossed plants were much more vigorous and more branched than the self-fertilised plants, and it is unfortunate that they were not weighed. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Taking all the evidence together, we must conclude that these strictly self-fertilised plants grew a little taller, were heavier, and generally flowered before those derived from a cross between two flowers on the same plant. Effects of Cross and Self Fertilisation in the Vegetable Kingdom I was so much surprised at this great superiority of the self-fertilised over the crossed plants, that I determined to try how they would behave in one of the pots during a second growth. Effects of Cross and Self Fertilisation in the Vegetable Kingdom In four out of the five pots a crossed plant flowered before any one of the self-fertilised. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The twelve crossed plants now averaged 33.28, and the ten self-fertilised 19.9 inches in height, or as 100 to 60; so that they differed somewhat less than before. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The self-fertilised seeds thus obtained from the crossed and self-fertilised plants, after germinating on sand, were planted on the opposite sides of four small pots, and treated as before. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The average height of the thirteen self-fertilised grandchildren of Hero is 79.76 inches, and that of the grandchildren from a cross between the self-fertilised children is 74.85; or as 100 to 94. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The seven self-fertilised plants from the crossed plants here average 15.73, and the seven self-fertilised from the self-fertilised 21 inches in height; or as 100 to 133. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The covered-up plant, however, produced altogether twenty-five spontaneously self-fertilised seeds; the exposed plant producing fifty-five seeds, the product, no doubt, of cross-fertilisation. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The self-fertilised plants thus exceeded the crossed in height by a little; but this was entirely due to the tallness of one of the self-fertilised. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The crossed plants in both pots flowered before the self-fertilised. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Diagram showing the mean heights of the crossed and self-fertilised plants of Ipomoea purpurea in the ten generations; the mean height of the crossed plants being taken as 100. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Uniform colour of the flowers on the self-fertilised plants of the fourth generation. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Nicotiana tabacum, crossed and self-fertilised plants of equal height. Effects of Cross and Self Fertilisation in the Vegetable Kingdom From this it follows that an equal number of crossed and self-fertilised capsules would have contained seeds by weight as 100 to 67. Effects of Cross and Self Fertilisation in the Vegetable Kingdom For some time the young crossed plants had no advantage in height over the self-fertilised; but their leaves were larger. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Therefore, of the seventy-three crossed plants, sixty-eight grew to a greater height than the self-fertilised plants, to which they were opposed. Effects of Cross and Self Fertilisation in the Vegetable Kingdom In Pot 3 both the crossed plants were killed at an early age by some animal, so that the self-fertilised had no competitors. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Nevertheless these two self-fertilised plants were measured, and are included in Table 6/77. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The crossed plants flowered long before their self-fertilised opponents in Pots 1 and 2, and before those growing separately in Pot 3. Effects of Cross and Self Fertilisation in the Vegetable Kingdom But this great inequality is in part accidental, owing to some of the self-fertilised plants being very short, and to one of the crossed being very tall. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Crossed capsules compared with self-fertilised capsules contained seeds in the ratio of : 100 to 94. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Twelve flowers on the self-fertilised plants were again fertilised with their own pollen and produced no less than twelve capsules, and the six finest of these contained by weight 2.57 grains of seeds. Effects of Cross and Self Fertilisation in the Vegetable Kingdom But as in the two succeeding generations the crossed plants resumed their former superiority over the self-fertilised, the case must be looked at as an anomaly. Effects of Cross and Self Fertilisation in the Vegetable Kingdom In three of the pots the self-fertilised plants flowered first; but in Pot 3 at the same time with the crossed. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The SELF-FERTILISED plants raised from these seeds form the fifth self-fertilised generation. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Capsules from flowers on the crossed plants fertilised by pollen from another plant, and capsules from flowers on the self-fertilised plants fertilised with their own pollen, contained seeds in the proportion of : 100 to 94. Effects of Cross and Self Fertilisation in the Vegetable Kingdom These latter plants and the intercrossed are comparable in all respects with the crossed and self-fertilised plants of the four previous generations. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Ten self-fertilised capsules would have contained 3.00 grains weight of seed. Effects of Cross and Self Fertilisation in the Vegetable Kingdom We thus get the following ratios:— Seeds from the Westerham-crossed capsules to those from the capsules of the fifth self-fertilised generation, in weight as 100 to 48. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Seeds from the intercrossed capsules to those from the self-fertilised capsules, in weight as 100 to 72. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The seeds produced by the crossed flowers on the crossed plants were not always heavier than the self-fertilised seeds on the self-fertilised plants. Effects of Cross and Self Fertilisation in the Vegetable Kingdom We thus get the following ratios:— The Westerham-crossed plants in height to the self-fertilised as 100 to 66. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The intercrossed plants in height to the self-fertilised as 100 to 61. Effects of Cross and Self Fertilisation in the Vegetable Kingdom These three lots of plants were also weighed; the Westerham-crossed plants weighed 28 ounces; the intercrossed plants, 41 ounces; and the self-fertilised, 14.75 ounces. Effects of Cross and Self Fertilisation in the Vegetable Kingdom We thus get the following ratios:— The Westerham-crossed plants in height to the self-fertilised as 100 to 63. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The lighter seeds, whether produced from crossed or self-fertilised flowers, generally germinated before the heavier seeds. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The Westerham-crossed plants in weight to the self-fertilised as 100 to 53. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The intercrossed plants in weight to the self-fertilised as 100 to 36. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Their leaves were of a brighter green than those of the intercrossed and self-fertilised plants. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The ten tallest self-fertilised plants produced only 44 capsules, weighing 22.35 grains. Effects of Cross and Self Fertilisation in the Vegetable Kingdom I may add that the crossed plants, with very few exceptions, flowered before their self-fertilised opponents, as might have been expected from their greater height and vigour. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The original mother-plant, from which the five successive self-fertilised generations were raised, bore dingy purple flowers. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The flowers on the intercrossed plants were mostly of the same tint, but not nearly so uniform as those on the self-fertilised plants, and many of them were pale, approaching almost to white. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The self-fertilised plants were also remarkably uniform in height, as judged by the eye; the intercrossed less so, whilst the Westerham-crossed plants varied much in height. Effects of Cross and Self Fertilisation in the Vegetable Kingdom In no case did the capsules from flowers fertilised with pollen from a distinct plant yield many more, and sometimes they yielded much fewer seeds than the capsules from self-fertilised flowers. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The impaired fertility of the self-fertilised plants was shown in another way, namely, by their anthers being smaller than those in the flowers on the crossed plants. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The much greater productiveness of the self-fertilised than of the crossed capsules can hardly be attributed to chance, as all the capsules of both lots were very fine and healthy ones. Effects of Cross and Self Fertilisation in the Vegetable Kingdom In all four pots a self-fertilised plant flowered before any one of the crossed. Effects of Cross and Self Fertilisation in the Vegetable Kingdom In Pot 4, in which the plants were extremely crowded, the two lots were at first equal; and ultimately the tallest crossed plant exceeded by a trifle the tallest self-fertilised plant. Effects of Cross and Self Fertilisation in the Vegetable Kingdom When these plants were in flower I neglected to measure them, but record in my notes that all four self-fertilised plants exceeded in height the four crossed plants by 2 or 3 inches. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The impaired fertility of the self-fertilised plants of the eighth generation was also shown in another manner, which may often be observed in hybrids—namely, by the first-formed flowers being sterile. Effects of Cross and Self Fertilisation in the Vegetable Kingdom This plan differs from that before followed, in which seedlings from crossed plants again crossed, have been compared with seedlings from self-fertilised plants again self-fertilised. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The seven crossed plants in the first of these two tables average 95.25, and the seven self-fertilised 79.6 inches in height; or as 100 to 83. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Column 3: From Self-fertilised Plant again self-fertilised, forming the third Self-fertilised generation. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Some other flowers on the same two plants were fertilised with their own pollen, and the seedlings thus raised from the fourth self-fertilised generation. Effects of Cross and Self Fertilisation in the Vegetable Kingdom All the self-fertilised plants of the seventh generation, and I believe of one or two previous generations, produced flowers of exactly the same tint, namely, of a rich dark purple. Effects of Cross and Self Fertilisation in the Vegetable Kingdom But as there was no uniform difference in height between the crossed and self-fertilised seedlings raised from the two plants, their heights have been added together in calculating the averages. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Even whilst quite young, the crossed seedlings manifestly had much broader and finer leaves than the self-fertilised seedlings. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The twelve tallest crossed plants in the two pots belonging to the two series average here 31.53, and the twelve tallest self-fertilised plants 17.21 inches in height; or as 100 to 54. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Of the twenty crossed plants, twelve had flowered; whilst of the twenty self-fertilised plants one alone had flowered. Effects of Cross and Self Fertilisation in the Vegetable Kingdom So did all the plants, without any exception, in the three succeeding generations of self-fertilised plants; and very many were raised on account of other experiments in progress not here recorded. Effects of Cross and Self Fertilisation in the Vegetable Kingdom This gives a ratio of 100 to 38 for the average number of seeds per capsule for the crossed and self-fertilised flowers. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The seeds obtained in the manner just described were placed on sand, and after germinating were planted in pairs,—three crossed and three self-fertilised plants on the opposite sides of four pots. Effects of Cross and Self Fertilisation in the Vegetable Kingdom These plants were left uncovered in the greenhouse; and the twelve crossed plants produced forty capsules, whilst the twelve self-fertilised plants produced only five; or as 100 to 12. Effects of Cross and Self Fertilisation in the Vegetable Kingdom I counted the seeds in one of the finest capsules on the crossed plants, and it contained seventy-three; whilst the finest of the five capsules produced by the self-fertilised plants contained only thirty-five good seeds. Effects of Cross and Self Fertilisation in the Vegetable Kingdom My attention was first called to this fact by my gardener remarking that there was no occasion to label the self-fertilised plants, as they could always be known by their colour. Effects of Cross and Self Fertilisation in the Vegetable Kingdom In the following year the crossed plants again bore many flowers before the self-fertilised bore a single one. Effects of Cross and Self Fertilisation in the Vegetable Kingdom In Pots 1 and 2 the self-fertilised plants did not produce a single flower-stem; in Pot 4 only one; and in Pot 3 six, of which the three tallest were measured. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Anagallis collina: Red variety crossed by blue variety, and red variety self-fertilised. Effects of Cross and Self Fertilisation in the Vegetable Kingdom There is therefore the same extraordinary difference in fertility between the crossed and self-fertilised plants as in the last genus, Cyclamen, which belongs to the same family of the Primulaceae. Effects of Cross and Self Fertilisation in the Vegetable Kingdom A cross between the children of Hero did not give to the grandchildren any advantage over the self-fertilised grandchildren raised from the self-fertilised children. Effects of Cross and Self Fertilisation in the Vegetable Kingdom For some time there was no marked difference in height between the two lots; and in Pot 3, Table 6/93, the self-fertilised plants were rather the tallest. Effects of Cross and Self Fertilisation in the Vegetable Kingdom How much proportional weight ought to be attributed to these two agencies,—the one tending to injure the self-fertilised offspring, and the other to benefit the crossed offspring,—cannot be determined. Effects of Cross and Self Fertilisation in the Vegetable Kingdom But in all four pots the plants raised from the union of distinct plants belonging to the same form, flowered before the offspring from the self-fertilised flowers. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Therefore the average height of the fifteen crossed plants in all three pots was 38.06 inches, and that of the fifteen self-fertilised plants 26.13 inches; or as 100 to 69. Effects of Cross and Self Fertilisation in the Vegetable Kingdom When the crossed seedlings were on an average half an inch high, the self-fertilised ones were only a quarter of an inch high. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The eight tallest crossed plants averaged 30.92, and the eight tallest self-fertilised 30.7 inches in height, or as 100 to 99; so that they were practically equal. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Nevertheless these plants produced plenty of seed, as they likewise did when covered by a net; they are therefore fully capable of self-fertilisation, and have probably been self-fertilised in this country for many generations. Effects of Cross and Self Fertilisation in the Vegetable Kingdom On one occasion I weighed 200 of the crossed and 106 of the self-fertilised seeds, and the relative weight of an equal number was as 100 for the crossed to 101.5 for the self-fertilised. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The three crossed plants averaged 32.79 inches, and the three self-fertilised 32.08 inches in height; so that they were nearly equal, the crossed having a slight advantage. Effects of Cross and Self Fertilisation in the Vegetable Kingdom When grown to their full height under the above unfavourable conditions, the four tallest crossed plants averaged 7.62, and the four tallest self-fertilised 5.87 inches in height; or as 100 to 77. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Some flowers on the self-fertilised plants of the last generation were also self-fertilised. Effects of Cross and Self Fertilisation in the Vegetable Kingdom From these two lots of seeds, ten crossed and twelve self-fertilised plants of equal ages were raised; and these were measured when fully grown. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The crossed averaged 36.98, and the self-fertilised averaged 37.42 inches in height; so that here again the two lots were nearly equal; but the self-fertilised had a slight advantage. Effects of Cross and Self Fertilisation in the Vegetable Kingdom From the two lots of seeds thus obtained, twenty-one crossed and nineteen self-fertilised plants of equal age, and forming the third generation, were raised in fourteen large pots. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Ten flowers on the crossed plants were fully expanded before one on the self-fertilised plants. Effects of Cross and Self Fertilisation in the Vegetable Kingdom If we consider all the plants of the three generations taken together, the thirty-four crossed plants average 35.98, and the thirty-four self-fertilised plants 36.39 inches in height; or as 100 to 101. Effects of Cross and Self Fertilisation in the Vegetable Kingdom In all four pots a crossed plant flowered before any one of the self-fertilised; but three of the plants did not flower at all. Effects of Cross and Self Fertilisation in the Vegetable Kingdom When the plants were a little over a foot in height they were measured, and the crossed plants averaged 13.38, and the self-fertilised 12.29 inches in height; or as 100 to 92. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The self-fertilised plants were in consequence not so much crowded as the crossed, and thus had an advantage over them. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Some flowers on the crossed plants were crossed with pollen from another plant, and the capsules thus produced contained a rather greater weight of seed than those on the self-fertilised plants again self-fertilised. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The effects of crossing a self-fertilised plant either by another self-fertilised plant or by an intercrossed plant of the old stock. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Preliminary remarks on the crossed and self-fertilised plants of the same stock. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The twenty-six exceptional cases considered, in which the crossed plants did not exceed greatly in height the self-fertilised. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Relative weights of the crossed and self-fertilised plants. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The four tallest crossed seedlings, at the time of flowering, averaged 8 inches in height, whilst the four tallest self-fertilised plants averaged only 4 inches. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Dianthus caryophyllus—offspring from plants of the third self-fertilised generation crossed by intercrossed plants of the third generation, compared with plants of fourth self-fertilised generation: 15 : 28.00 : 10 : 26.55 : 95. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Brassica oleracea—offspring of plants self-fertilised for two generations and then crossed by a fresh stock, compared with plants of the third self-fertilised generation, by weight: 6 : : 6 : : 22. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Eschscholtzia californica—offspring of a Brazilian stock crossed by an English stock, compared with plants of the Brazilian stock of the second self-fertilised generation, in weight: .. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Eschscholtzia californica—offspring of a Brazilian stock crossed by an English stock, compared with plants of the Brazilian stock of the second self-fertilised generation, in fertility: .. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Crossed seeds were sown by themselves in a second small pot, and self-fertilised seeds were sown by themselves in a third small pot so that there was no competition whatever between these two lots. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Dianthus caryophyllus—offspring of plants self-fertilised for three generations and then crossed by a fresh stock, compared with plants of the fourth self-fertilised generation: 16 : 32.82 : 10 : 26.55 : 81. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Petunia violacea—offspring of plants self-fertilised for four generations and then crossed by a fresh stock, compared with plants of the fifth self-fertilised generation, in height: 21 : 50.05 : 21 : 33.23 : 66. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Petunia violacea—offspring of plants self-fertilised for four generations and then crossed by a fresh stock, compared with plants of the fifth self-fertilised generation, grown in open ground, in weight: .. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Nicotiana tabacum—offspring of plants self-fertilised for three generations and then crossed by a slightly different variety, compared with plants of the fourth self-fertilised generation, grown much crowded in pots, in weight: .. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Nevertheless the crossed plants grew from 1 to 2 inches higher on an average than the self-fertilised. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Nicotiana tabacum—offspring of plants self-fertilised for three generations and then crossed by a slightly different variety, compared with plants of the fourth self-fertilised generation, grown in open ground, in weight: .. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Anagallis collina—offspring from a red variety crossed by a blue variety, compared with the self-fertilised offspring of the red variety, in fertility: .. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Primula veris—offspring from long-styled plants of the third illegitimate generation, crossed by a fresh stock, compared with plants of the fourth illegitimate and self-fertilised generation: 8 : 7.03 : 8 : 3.21 : 46. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Primula veris—offspring from long-styled plants of the third illegitimate generation, crossed by a fresh stock, compared with plants of the fourth illegitimate and self-fertilised generation, in fertility: .. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Both lots looked equally vigorous, but the crossed plants flowered earlier and more profusely than the self-fertilised. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Primula veris—offspring from long-styled plants of the third illegitimate generation, crossed by a fresh stock, compared with plants of the fourth illegitimate and self-fertilised generation, in fertility in following year: .. Effects of Cross and Self Fertilisation in the Vegetable Kingdom In my experiments the greatest care was taken that in each generation all the crossed and self-fertilised plants should be subjected to the same conditions. Effects of Cross and Self Fertilisation in the Vegetable Kingdom During the three first generations the intercrossed plants taken together exceeded in height the self-fertilised taken together, in the ratio of 100 to 65, and in fertility in a still higher degree. Effects of Cross and Self Fertilisation in the Vegetable Kingdom In the fourth generation a new variety, which grew taller and had whiter and larger flowers than the old varieties, began to prevail, especially amongst the self-fertilised plants. Effects of Cross and Self Fertilisation in the Vegetable Kingdom And now another remarkable change was clearly perceived, namely, that the self-fertilised plants had become more self-fertile than the crossed. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Thus in the seventh generation the intercrossed plants were to the self-fertilised in height as 100 to 137. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Two plants of this variety of Mimulus, belonging to the sixth self-fertilised generation, and growing in separate pots, were intercrossed; and some flowers on the same plants were again self-fertilised. Effects of Cross and Self Fertilisation in the Vegetable Kingdom But this cross did not do the least good, the intercrossed plants being inferior in height to the self-fertilised, in the ratio of 100 to 110. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The plants derived from a cross between the self-fertilised plants exceeded in height by a little the self-fertilised, namely, as 100 to 92; and in fertility in a greater degree, namely, as 100 to 73. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The pots were all put under a net to exclude insects, and the crossed plants produced spontaneously only fifty-five capsules, whilst the self-fertilised plants produced eighty-one capsules, or as 100 to 147. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Some flowers on cabbage plants of the second self-fertilised generation were crossed with pollen from a plant of the same variety brought from a distant garden, and other flowers were again self-fertilised. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Plants derived from a cross with a fresh stock and plants of the third self-fertilised generation were thus raised. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Plants self-fertilised for three generations were crossed with pollen from a fresh stock, and their offspring were grown in competition with plants of the fourth self-fertilised generation. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The latter in the fourth generation were crossed by a fresh stock, and the seedlings thus obtained were put into competition with the self-fertilised plants of the fifth generation. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The seeds from nine capsules of both lots were placed in separate watch-glasses for comparison, and the self-fertilised appeared rather the more numerous. Effects of Cross and Self Fertilisation in the Vegetable Kingdom My plants were remarkably self-fertile, and the capsules from the self-fertilised flowers apparently yielded more seeds than those which were cross-fertilised. Effects of Cross and Self Fertilisation in the Vegetable Kingdom These crossed plants, when thus subjected to severe competition, also exceeded the self-fertilised in weight in the ratio of 100 to 37. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Plants raised from a red variety crossed by another plant of the same variety were in height to the self-fertilised plants from the red variety as 100 to 73. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The plants raised from this cross between the two varieties were to the self-fertilised seedlings from the red variety, in height as 100 to 66, and in fertility as 100 to 6. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Lastly, other flowers on the same plants of the eighth self-fertilised generation were crossed with pollen taken from plants which had been raised from seed procured from a garden at Chelsea. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Of such cases, that is, of self-fertilised plants of which the mean height is expressed by figures between 95 and 105, there are eighteen, either in some one or all the generations. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Nevertheless, when the eight crossed and eight self-fertilised plants were cut down and weighed, the former were to the latter in weight as 100 to 49! Effects of Cross and Self Fertilisation in the Vegetable Kingdom Eight crossed plants were to eight self-fertilised of the third generation in average height as 100 to 131; and at an early age the crossed were inferior even in a still higher degree. Effects of Cross and Self Fertilisation in the Vegetable Kingdom In two other cases the crossed equalled the self-fertilised in height within five per cent; and in the fourth case the self-fertilised exceeded the crossed by above this limit. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Therefore the Chelsea-crossed are to the intercrossed in height as 100 to 56; the Chelsea-crossed to the self-fertilised as 100 to 52; and the intercrossed to the self-fertilised as 100 to 92. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The intercrossed plants thus have at least one important advantage over the self-fertilised. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Moreover, the flowers on the parent-plants when fertilised with pollen from another individual of the same stock yield far more seeds than when self-fertilised; the flowers in this latter case being often quite sterile. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Moreover, the flowers on the parent-plants which were crossed and self-fertilised, yielded seeds on one occasion in the proportion of 100 to 38, and on a second occasion in the proportion of 100 to 58. Effects of Cross and Self Fertilisation in the Vegetable Kingdom So that there can be no doubt about the beneficial effects of a cross, although the mean height of the crossed plants was only three per cent above that of the self-fertilised plants. Effects of Cross and Self Fertilisation in the Vegetable Kingdom With respect to fertility, the twenty-eight Chelsea-crossed plants produced 272 capsules; the twenty-seven intercrossed plants produced 24; and the seventeen self-fertilised plants 17 capsules. Effects of Cross and Self Fertilisation in the Vegetable Kingdom In all four pots a crossed plant flowered before any one of the self-fertilised plants, and this is usually a safe indication of some real superiority in the crossed plants. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The flowers on the parent-plants which were crossed with pollen from another plant yielded seeds compared with the self-fertilised flowers in the ratio of 100 to 72. Effects of Cross and Self Fertilisation in the Vegetable Kingdom All four crossed plants flowered before their self-fertilised opponents. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The five crossed plants were to the five self-fertilised in height as 100 to 96. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Here the average height of the twenty-two crossed plants is 16.85, and that of the twenty-two self-fertilised plants 16.07; or as 100 to 95. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The eight crossed plants were to the eight self-fertilised in height as 100 to 107. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Only four pairs were raised, and the crossed were to the self-fertilised in height as 100 to 109. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Deducting these fourteen cases, there remain twelve in which the crossed plants show no well-marked advantage over the self-fertilised. Effects of Cross and Self Fertilisation in the Vegetable Kingdom On the other hand, we have seen that there are fifty-seven cases in which the crossed plants exceed the self-fertilised in height by at least five per cent, and generally in a much higher degree. Effects of Cross and Self Fertilisation in the Vegetable Kingdom In one instance crossed and self-fertilised seedlings, grown in rich soil and not put into competition with each other, attained to an equal height. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The crossed and self-fertilised offspring from a partially self-sterile plant of Reseda odorata were almost equal in weight, though not in height. Effects of Cross and Self Fertilisation in the Vegetable Kingdom This was evidently the case with the crossed plants of Viola tricolor, which ultimately quite overwhelmed the self-fertilised. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The seedlings were thus subjected to very severe competition with plants of other kinds; and in all such cases, the crossed seedlings exhibited a great superiority in their power of growth over the self-fertilised. Effects of Cross and Self Fertilisation in the Vegetable Kingdom In such cases the crossed plants almost invariably showed a greater superiority over the self-fertilised, than did the plants which grew in pairs in the pots. Effects of Cross and Self Fertilisation in the Vegetable Kingdom This victorious self-fertilised plant consisted of a new white-flowered variety, which grew taller than the old yellowish varieties. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Sometimes crossed and self-fertilised seeds were sown in separate rows in the open ground, which was kept clear of weeds; so that the seedlings were not subjected to any competition with other kinds of plants. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Thus with the plants of Digitalis, which competed together in pots, the crossed were to the self-fertilised in height as 100 to 70; whilst those which were grown separately were only as 100 to 85. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The crossed plants always withstood the injurious effects of being suddenly removed into the open air after having been kept in the greenhouse better than did the self-fertilised. Effects of Cross and Self Fertilisation in the Vegetable Kingdom This was manifestly the case with some crossed and self-fertilised plants of Ipomoea, which were suddenly moved from the hothouse to the coldest part of a cool greenhouse. Effects of Cross and Self Fertilisation in the Vegetable Kingdom From the first it seemed to be rather more fertile, when self-fertilised, than the old varieties, and in the succeeding self-fertilised generations became more and more self-fertile. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The offspring of plants of the eighth self-fertilised generation of Mimulus crossed by a fresh stock, survived a frost which killed every single self-fertilised and intercrossed plant of the same old stock. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Nearly the same result followed with some crossed and self-fertilised plants of Viola tricolor. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Young crossed seedlings of Nicotiana withstood a cold and wet summer much better than the self-fertilised seedlings. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Independently of any external cause which could be detected, the self-fertilised plants were more liable to premature death than were the crossed; and this seems to me a curious fact. Effects of Cross and Self Fertilisation in the Vegetable Kingdom In the sixth generation the self-fertilised plants of this variety compared with the crossed plants produced capsules in the proportion of 147 to 100, both lots being allowed to fertilise themselves spontaneously. Effects of Cross and Self Fertilisation in the Vegetable Kingdom With Beta vulgaris, however, it is certain that a large number of the self-fertilised seeds perished after germinating beneath the ground, whereas the crossed seeds sown at the same time did not thus suffer. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The self-fertilised plants of Petunia completed their growth and began to wither sooner than did the intercrossed plants; and these latter considerably before the offspring from a cross with a fresh stock. Effects of Cross and Self Fertilisation in the Vegetable Kingdom With a large number of species, the crossed plants exhibited a well-marked tendency to flower before the self-fertilised ones growing in the same pots. Effects of Cross and Self Fertilisation in the Vegetable Kingdom I record in my notes that in all ten generations many of the crossed plants flowered before the self-fertilised; but no details were kept. Effects of Cross and Self Fertilisation in the Vegetable Kingdom In the second trial, the intercrossed plants were more fertile than the self-fertilised in the ratio of 100 to 73, and taller in the ratio of 100 to 92. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Ten flowers on the crossed plants were fully expanded before one on the self-fertilised. Effects of Cross and Self Fertilisation in the Vegetable Kingdom In both these generations a crossed plant flowered before one of the self-fertilised in all three pots. Effects of Cross and Self Fertilisation in the Vegetable Kingdom In all three pots a crossed plant flowered first; yet the self-fertilised plants, which belonged to the new tall variety, were in height to the crossed as 126 to 100. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Plants derived from a cross with a fresh stock as well as the intercrossed plants of the old stock, flowered before the self-fertilised plants in nine out of the ten pots. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Notwithstanding that the self-fertilised plants in the second trial were the product of two additional generations of self-fertilisation, I cannot understand this discordance in the results of the two analogous experiments. Effects of Cross and Self Fertilisation in the Vegetable Kingdom A crossed plant flowered before any one of the self-fertilised in all three pots. Effects of Cross and Self Fertilisation in the Vegetable Kingdom During two successive seasons several crossed plants flowered before the self-fertilised. Effects of Cross and Self Fertilisation in the Vegetable Kingdom A crossed plant in three out of the four pots flowered before any one of the self-fertilised. Effects of Cross and Self Fertilisation in the Vegetable Kingdom A crossed plant in five out of the six pots flowered before any one of the self-fertilised. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Of the twenty-four spontaneously self-fertilised capsules, only two contained their full complement of seed; six contained a moderate supply; and the remaining sixteen extremely few seeds. Effects of Cross and Self Fertilisation in the Vegetable Kingdom In two large beds of plants, four of the crossed plants flowered before any one of the self-fertilised. Effects of Cross and Self Fertilisation in the Vegetable Kingdom In three out of the four pots a crossed plant flowered first; yet the crossed were to the self-fertilised in height only as 100 to 99, but in weight as 100 to 49. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Plants derived from a cross with a fresh stock, and the intercrossed plants of the old stock, both flowered before the self-fertilised in nine out of the ten pots. Effects of Cross and Self Fertilisation in the Vegetable Kingdom In three out of the four pots a crossed plant flowered before any one of the self-fertilised; yet the latter were to the crossed in height as 109 to 100. Effects of Cross and Self Fertilisation in the Vegetable Kingdom We may put the result in another way: the number of flower-stems on the crossed plants was to those on an equal number of self-fertilised plants as 100 to 48. Effects of Cross and Self Fertilisation in the Vegetable Kingdom A crossed plant flowered before any one of the self-fertilised in three out of the four pots, and simultaneously in the fourth pot. Effects of Cross and Self Fertilisation in the Vegetable Kingdom A crossed plant flowered before any one of the self-fertilised in four out of the five pots. Effects of Cross and Self Fertilisation in the Vegetable Kingdom In all four pots a crossed plant flowered before any one of the self-fertilised. Effects of Cross and Self Fertilisation in the Vegetable Kingdom In all four pots a crossed plant flowered some days before any one of the self-fertilised. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Three crossed seeds in a state of germination were also planted in three separate pots; and three self-fertilised seeds in the same state in three other pots. Effects of Cross and Self Fertilisation in the Vegetable Kingdom A plant derived from a cross with a fresh stock flowered before any one of the self-fertilised plants of the fourth generation, in fifteen out of the sixteen pots. Effects of Cross and Self Fertilisation in the Vegetable Kingdom During two successive seasons a crossed plant flowered some weeks before any one of the self-fertilised in all four pots. Effects of Cross and Self Fertilisation in the Vegetable Kingdom In all four pots plants derived from an illegitimate cross between distinct plants flowered before any one of the self-fertilised plants. Effects of Cross and Self Fertilisation in the Vegetable Kingdom A legitimately crossed plant flowered before any one of the self-fertilised plants in seven out of the eight pots. Effects of Cross and Self Fertilisation in the Vegetable Kingdom We here see that two of the self-fertilised plants exceed in height their crossed opponents. Effects of Cross and Self Fertilisation in the Vegetable Kingdom A legitimately crossed plant flowered from one to two days before any one of the self-fertilised plants in all three pots. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The crossed plants flowered before the self-fertilised in the open ground, but simultaneously in the pots. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Although the crossed plants were to the self-fertilised in height as 100 to 82; yet in all three pots the self-fertilised plants flowered first. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Although the crossed plants were, as in the last case, to the self-fertilised in height as 100 to 82, yet in the two pots the self-fertilised flowered first. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Nevertheless the average height of the six crossed plants is 65.34 inches, and that of the six self-fertilised plants 56.5 inches; or as 100 to 86. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The crossed plants were to the self-fertilised in height only as 100 to 127, and the latter flowered much before the crossed. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The crossed plants were to the self-fertilised in height as 100 to 131, and in three out of the four pots a self-fertilised plant flowered first; in the fourth pot simultaneously. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The crossed plants were to the self-fertilised in height only as 100 to 178, and a self-fertilised plant flowered first in all four pots. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The crossed plants were to the self-fertilised in height as 100 to 101, and in four out of the five pots a self-fertilised plant flowered first. Effects of Cross and Self Fertilisation in the Vegetable Kingdom They are not easy to fertilise artificially, and it is possible that some of the flowers which I thought that I had succeeded in crossing were afterwards spontaneously self-fertilised under the net. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Although the crossed plants were to the self-fertilised in height as 100 to 88, yet there was no marked difference in their period of flowering. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Although the crossed plants were to the self-fertilised in height as 100 to 91, yet they flowered simultaneously. Effects of Cross and Self Fertilisation in the Vegetable Kingdom These three lists include fifty-eight cases, in which the period of flowering of the crossed and self-fertilised plants was recorded. Effects of Cross and Self Fertilisation in the Vegetable Kingdom In forty-four of them a crossed plant flowered first either in a majority of the pots or in all; in nine instances a self-fertilised plant flowered first, and in five the two lots flowered simultaneously. Effects of Cross and Self Fertilisation in the Vegetable Kingdom I may add that fifteen capsules from self-fertilised cleistogene flowers contained on an average sixty-four seeds, with a maximum in one of eighty-seven. Effects of Cross and Self Fertilisation in the Vegetable Kingdom One of the most striking cases is that of Cyclamen, in which the crossed plants flowered some weeks before the self-fertilised in all four pots during two seasons. Effects of Cross and Self Fertilisation in the Vegetable Kingdom In the second generation of Lobelia ramosa, a crossed plant flowered in all four pots some days before any one of the self-fertilised. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Thus the crossed plants both of Lupinus luteus and Clarkia elegans were to the self-fertilised plants in height as 100 to 82, and yet the latter flowered first. Effects of Cross and Self Fertilisation in the Vegetable Kingdom In the third generation of Nicotiana, and in all three generations of Canna, the crossed and self-fertilised plants were of nearly equal height, yet the self-fertilised tended to flower first. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The crossed plants when in full flower averaged 4.3 inches, and the self-fertilised plants from the perfect flowers 4.27 inches in height; or as 100 to 99. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The crossed plants of Hibiscus were inferior in height to the self-fertilised, in the ratio of 100 to 109, and yet they flowered before the self-fertilised in three out of the four pots. Effects of Cross and Self Fertilisation in the Vegetable Kingdom In all three pots of Viola tricolor, naturally crossed plants the offspring of crossed plants flowered before naturally crossed plants the offspring of self-fertilised plants. Effects of Cross and Self Fertilisation in the Vegetable Kingdom In eight pots, in which the plants did not grow much crowded, the flower-stems on sixteen intercrossed plants were in height to those on sixteen self-fertilised plants, as 100 to 94. Effects of Cross and Self Fertilisation in the Vegetable Kingdom In the two other pots on which the plants grew much crowded, the flower-stems on nine intercrossed plants were in height to those on nine self-fertilised plants, as 100 to 90. Effects of Cross and Self Fertilisation in the Vegetable Kingdom I determined to compare again the growth of plants raised from crossed and self-fertilised perfect flowers, and obtained two fresh lots of seeds. Effects of Cross and Self Fertilisation in the Vegetable Kingdom That the intercrossed plants in these two latter pots had a real advantage over their self-fertilised opponents, was well shown by their relative weights when cut down, which was as 100 to 78. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The mean height of the flower-stems on the twenty-five intercrossed plants in the ten pots taken together, was to that of the flower-stems on the twenty-five self-fertilised plants, as 100 to 92. Effects of Cross and Self Fertilisation in the Vegetable Kingdom So that the self-fertilised plants were a little taller than the intercrossed; and in eight out of the ten pots a self-fertilised plant flowered before any one of the crossed plants in the same pots. Effects of Cross and Self Fertilisation in the Vegetable Kingdom To this subject of the superiority of the self-fertilised plants in certain cases, I shall have to recur in a future chapter. Effects of Cross and Self Fertilisation in the Vegetable Kingdom All these plants were then cut down close to the ground, and the forty-seven crossed plants weighed 1090.3 grains, and the forty-one self-fertilised plants weighed 887.4 grains. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Moreover, in seven out of the eight pots a self-fertilised plant flowered before any of the intercrossed plants. Effects of Cross and Self Fertilisation in the Vegetable Kingdom So that here again the self-fertilised exhibit a slight superiority over the intercrossed plants. Effects of Cross and Self Fertilisation in the Vegetable Kingdom For the sake of comparison, I may add that seedlings raised during three generations from a cross between distinct plants were to the self-fertilised plants in height as 100 to 65. Effects of Cross and Self Fertilisation in the Vegetable Kingdom These differed much in height, the crossed plants being to the self-fertilised as 100 to 86. Effects of Cross and Self Fertilisation in the Vegetable Kingdom From these several facts we may conclude that the crossed plants had some real, though very slight, advantage in height and weight over the self-fertilised plants, when grown in competition with one another. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The crossed plants flowered first, and produced exactly twice as many flower-stems; and they afterwards increased by stolons to such an extent as almost to overwhelm the self-fertilised plants. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Indeed, in two of the cases the self-fertilised plants were superior to such intercrossed plants. Effects of Cross and Self Fertilisation in the Vegetable Kingdom We have seen that seedlings from a cross between distinct plants almost always exceed their self-fertilised opponents in height, weight, and constitutional vigour, and, as will hereafter be shown, often in fertility. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Firstly, seedlings were raised from self-fertilised seeds produced under a net by crossed and self-fertilised plants of Nemophila insignis; and the latter were to the former in height as 133 to 100. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The crossed plants were, however, inferior in fertility to the self-fertilised. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Those from the crossed plants flowered in all three pots before those from the self-fertilised plants; and when fully grown the former were to the latter in height as 100 to 82. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Those from the self-fertilised plants which had been crossed during the two previous generations were to those from the plants self-fertilised during many previous generations in height as 100 to 90. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Nevertheless, the flowers produced by the self-fertilised plants of the above four species became absolutely uniform in tint, or very nearly so, after they had been grown for some generations under closely similar conditions. Effects of Cross and Self Fertilisation in the Vegetable Kingdom A tall variety, bearing large, almost white flowers blotched with crimson, appeared amongst the intercrossed and self-fertilised plants of the third and fourth generations. Effects of Cross and Self Fertilisation in the Vegetable Kingdom When two-thirds grown, the two tallest plants on each side of each pot were measured; the crossed averaged 16.37 inches, and the self-fertilised 11.75 in height; or as 100 to 71. Effects of Cross and Self Fertilisation in the Vegetable Kingdom This variety increased so rapidly, that in the sixth generation of self-fertilised plants every single one consisted of it. Effects of Cross and Self Fertilisation in the Vegetable Kingdom So it was with all the many plants which were raised, up to the last or ninth self-fertilised generation. Effects of Cross and Self Fertilisation in the Vegetable Kingdom My attention was first drawn to the present subject by observing that the flowers on all the plants of the seventh self-fertilised generation were of a uniform, remarkably rich, dark purple tint. Effects of Cross and Self Fertilisation in the Vegetable Kingdom This dark purple variety did not appear, as far as my gardener and myself could recollect, before the fifth or sixth self-fertilised generation. Effects of Cross and Self Fertilisation in the Vegetable Kingdom So that the crossed plants in this respect were far more productive than the self-fertilised. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The intercrossed plants of the third generation likewise produced flowers almost, though not quite so uniform in tint as those of the self-fertilised plants. Effects of Cross and Self Fertilisation in the Vegetable Kingdom In this case I happened to record in my notes that the flowers on the parent-plant which was first self-fertilised were of a "dingy purple colour." Effects of Cross and Self Fertilisation in the Vegetable Kingdom I regret that I did not attend to the uniformity in height of the self-fertilised seedlings in the later generations of the other species. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Fertility of plants of crossed and self-fertilised parentage, both lots being fertilised in the same manner. Effects of Cross and Self Fertilisation in the Vegetable Kingdom When fully grown, the tallest crossed plant in one pot was a very little taller than the tallest self-fertilised plant on the opposite side, and in the other pot exactly the reverse occurred. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Fertility of the parent-plants when first crossed and self-fertilised, and of their crossed and self-fertilised offspring when again crossed and self-fertilised. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Relative weights and rates of germination of seeds from crossed and self-fertilised flowers. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Secondly, the degree of innate fertility or sterility of the seedlings raised from crossed and self-fertilised seeds; such seedlings being of the same age, grown under the same conditions, and fertilised in the same manner. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The cases observed by me are given in Table 9/D, in which plants of crossed and self-fertilised parentage were left to fertilise themselves, being either crossed by insects or spontaneously self-fertilised. Effects of Cross and Self Fertilisation in the Vegetable Kingdom In the following summer all the self-fertilised and some of the quasi-crossed plants were covered by a net. Effects of Cross and Self Fertilisation in the Vegetable Kingdom It need hardly be added that in Table 9/D the same number of crossed and self-fertilised plants are always compared. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Ipomoea purpurea—first generation: seeds per capsule on crossed and self-fertilised plants, not growing much crowded, spontaneously self-fertilised under a net, in number: 99. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Ipomoea purpurea—seeds per capsule on crossed and self-fertilised plants from the same parents as in the last case, but growing much crowded, spontaneously self-fertilised under a net, in number: 93. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Ipomoea purpurea—third generation: seeds per capsule on crossed and self-fertilised plants, spontaneously self-fertilised under a net, in number: 94. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Many flowers on the self-fertilised plants were artificially self-fertilised, and others were allowed to fertilise themselves spontaneously under the net, but they yielded altogether very few seeds. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Ipomoea purpurea—fifth generation: seeds per capsule on crossed and self-fertilised plants, left uncovered in the hothouse, and spontaneously fertilised: 89. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Ipomoea purpurea—ninth generation: number of capsules on crossed plants to those on self-fertilised plants, spontaneously self-fertilised under a net: 26. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Salvia coccinea—crossed plants, compared with self-fertilised plants, produced flowers, in number: 57. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Iberis umbellata—plants left uncovered in greenhouse; intercrossed plants of the 3rd generation, compared with self-fertilised plants of the 3rd generation, yielded seeds, in number: 75. Effects of Cross and Self Fertilisation in the Vegetable Kingdom At a very early age the crossed plants showed some superiority over the self-fertilised, which was ever afterwards retained. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Iberis umbellata—plants from a cross between two varieties, compared with self-fertilised plants of the 3rd generation, yielded seeds, by weight : 75. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Papaver vagum—crossed and self-fertilised plants, left uncovered, produced capsules, in number: 99. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Eschscholtzia californica—Brazilian stock; plants left uncovered and cross-fertilised by bees; capsules on intercrossed plants of the 2nd generation, compared with capsules on self-fertilised plants of 2nd generation, contained seeds, in number: 78. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Viola tricolor—crossed and self-fertilised plants, left uncovered and cross-fertilised by bees, produced capsules in number: 10. Effects of Cross and Self Fertilisation in the Vegetable Kingdom When the plants were fully grown, the two tallest crossed and the two tallest self-fertilised plants in each pot were measured, as shown in Table 3/28. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Delphinium consolida—crossed and self-fertilised plants, left uncovered in the greenhouse, produced capsules in number: 56. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Dianthus caryophyllus—plants spontaneously self-fertilised under a net; capsules on intercrossed and self-fertilised plants of the 3rd generation contained seeds in number: 125. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Tropaeolum minus—crossed and self-fertilised plants, left uncovered in the greenhouse, produced seeds in number: 64. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Lathyrus odoratus—crossed and self-fertilised plants of the 2nd generation, left uncovered in the greenhouse, but certainly self-fertilised, produced pods in number: 91. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Early in the following summer the superiority of the crossed plants, owing to their increase by stolons, over the self-fertilised plants was truly wonderful. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Nemophila insignis—crossed and self-fertilised plants, covered by a net and spontaneously self-fertilised in the greenhouse, produced capsules in number: 29. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Petunia violacea—left uncovered and cross-fertilised by insects: plants of the 5th intercrossed and self-fertilised generations produced seeds, as judged by the weight of an equal number of capsules: 86. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Cyclamen persicum—crossed and self-fertilised plants, left uncovered in the greenhouse, produced capsules in number: 12. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Anagallis collina—crossed and self-fertilised plants, left uncovered in the greenhouse, produced capsules in number: 8. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Eschscholtzia californica, seedlings from a cross with a fresh stock not more vigorous, but more fertile than the self-fertilised seedlings. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The fertility of the crossed plants is represented in Table 9/D by 100, and that of the self-fertilised by the other figures. Effects of Cross and Self Fertilisation in the Vegetable Kingdom In only two instances in the table, namely, with Vandellia and in the third generation of Dianthus, the capsules on the self-fertilised plants contained more seed than those on the crossed plants. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Excluding the seven cases now referred to, there remain twenty-six in which the crossed plants were manifestly much more fertile, sometimes to an extraordinary degree, than the self-fertilised with which they grew in competition. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Of such cases there are twelve in the table, and the mean of their mean fertility is as 100 for the crossed plants, to 59 for the self-fertilised plants. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Dianthus caryophyllus, crossed and self-fertilised plants compared for four generations. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The self-fertilised plants belong to the 9th generation: 100 : 4 : 3. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Eschscholtzia californica—the intercrossed and self-fertilised plants belong to the 2nd generation: 100 : 45 : 40. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Dianthus caryophyllus—the intercrossed plants are derived from self-fertilised of the 3rd generation, crossed by intercrossed plants of the 3rd generation. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The self-fertilised plants belong to the 4th generation: 100 : 45 : 33. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Uniform colour of the flowers on the self-fertilised plants. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Petunia violacea—the intercrossed and self-fertilised plants belong to the 5th generation: 100 : 54 : 46. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Table 9/E further shows us that in all four cases the intercrossed plants of the same stock still have a decided though small advantage in fertility over the self-fertilised plants. Effects of Cross and Self Fertilisation in the Vegetable Kingdom In the seventh and eighth generation of Ipomoea, the anthers in the flowers of the self-fertilised plants were plainly smaller than those in the flowers of the intercrossed plants. Effects of Cross and Self Fertilisation in the Vegetable Kingdom In the fourth generation of Petunia, the pollen produced by the self-fertilised and intercrossed plants was compared, and they were far more empty and shrivelled grains in the former. Effects of Cross and Self Fertilisation in the Vegetable Kingdom This variety produced plenty of spontaneously self-fertilised seed under a net. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Thirty flowers on some plants of this species were crossed and produced twenty-seven capsules, each containing five seeds; thirty-two flowers on the same plants were self-fertilised and produced only six capsules, each containing five seeds. Effects of Cross and Self Fertilisation in the Vegetable Kingdom As the number of seeds per capsule is here the same, the fertility of the crossed and self-fertilised flowers is given in Table 9/F as equal, or as 100 to 100. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Linaria vulgaris—crossed and self-fertilised flowers yielded seeds as: 14. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Brassica oleracea—crossed and self-fertilised flowers yielded seeds as: 25. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Consequently seeds supposed to have been thus crossed and spontaneously self-fertilised seeds were sown on opposite sides of a pot. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Dianthus caryophyllus—crossed and self-fertilised flowers yielded seeds as: 92. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Tropaeolum minus—crossed and self-fertilised flowers yielded seeds as: 92. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Borago officinalis—crossed and self-fertilised flowers yielded seeds as: 60. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Table 9/G gives the relative fertility of flowers on crossed plants again cross-fertilised, and of flowers on self-fertilised plants again self-fertilised, either in the first or in a later generation. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The plants in Pots 1 and 2 were measured when between 7 and 8 inches in height, and the crossed exceeded the self-fertilised in average height by 1.57 inches. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Ipomoea purpurea—crossed and self-fertilised flowers on the crossed and self-fertilised plants of the first generation yielded seeds as: 93. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Ipomoea purpurea—crossed and self-fertilised flowers on the crossed and self-fertilised plants of the 3rd generation yielded seeds as: 94. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Ipomoea purpurea—crossed and self-fertilised flowers on the crossed and self-fertilised plants of the 4th generation yielded seeds as: 94. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Ipomoea purpurea—crossed and self-fertilised flowers on the crossed and self-fertilised plants of the 5th generation yielded seeds as: 107. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The average height of the seven crossed plants is here 19.12 inches, and that of the seven self-fertilised plants 16.39, or as 100 to 86. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Viola tricolor—crossed and self-fertilised flowers on the crossed and self-fertilised plants of the 1st generation yielded seeds as: 69. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Dianthus caryophyllus—crossed and self-fertilised flowers on the crossed and self-fertilised plants of the 1st generation yielded seeds as: 65. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Dianthus caryophyllus—flowers on self-fertilised plants of the 3rd generation crossed by intercrossed plants, and other flowers again self-fertilised yielded seeds as: 97. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Dianthus caryophyllus—flowers on self-fertilised plants of the 3rd generation crossed by a fresh stock, and other flowers again self-fertilised yielded seeds as: 127. Effects of Cross and Self Fertilisation in the Vegetable Kingdom But as the plants on the self-fertilised side grew very unequally, this ratio cannot be fully trusted, and is probably too high. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Anagallis collina—flowers on red variety crossed by a blue variety, and other flowers on the red variety self-fertilised yielded seeds as: 48. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Canna warscewiczi—crossed and self-fertilised flowers on the crossed and self-fertilised plants of three generations taken together yielded seeds as: 85. Effects of Cross and Self Fertilisation in the Vegetable Kingdom The flowers on many other species were crossed and self-fertilised, but as only a few were thus treated, the results cannot be trusted, as far as fertility is concerned, and are not here given. Effects of Cross and Self Fertilisation in the Vegetable Kingdom There are fifteen cases in the two tables in which the number of seeds per capsule produced by the self-fertilised flowers equals or even exceeds that yielded by the crossed flowers. Effects of Cross and Self Fertilisation in the Vegetable Kingdom We thus get the ratio of 100 to 81, for the number of seed-bearing flower-heads produced by the crossed and self-fertilised plants. Effects of Cross and Self Fertilisation in the Vegetable Kingdom On the other hand, the crossed seedlings of Eschscholtzia were neither taller nor heavier than the self-fertilised, although the crossed flowers were far more productive than the self-fertilised. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Thus the crossed and self-fertilised plants of Ipomoea, Papaver, Reseda odorata, and Limnanthes were almost equally fertile, yet the former exceeded considerably in height the self-fertilised plants. Effects of Cross and Self Fertilisation in the Vegetable Kingdom On the other hand, the crossed and self-fertilised plants of Mimulus and Primula differed to an extreme degree in innate fertility, but by no means to a corresponding degree in height or vigour. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Thunbergia alata kept by me in a warm greenhouse was self-sterile early in the season, but at a later period produced many spontaneously self-fertilised fruits. Effects of Cross and Self Fertilisation in the Vegetable Kingdom Later in the season twelve other flowers on these two plants were artificially self-fertilised; but they yielded only two capsules, containing three and six seeds. Effects of Cross and Self Fertilisation in the Vegetable Kingdom One of these soon became covered with spontaneously self-fertilised capsules, as numerous as those on the surrounding unprotected plants; so that it was evidently quite self-fertile. Effects of Cross and Self Fertilisation in the Vegetable Kingdom |
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