| 单词 | cotyledon |
| 例句 | Microgreens are simply the cotyledons or seed leaves, that first emerge from a seed when it germinates. Microgreens: the health-giving shoots explained 2023-09-07T04:00:00Z The cotyledons serve as conduits to transmit the broken-down food reserves from their storage site inside the seed to the developing embryo. Fundamentals of Biology 2015-01-01T00:00:00Z The flowering plants are divided into two main groups—the monocots and eudicots—according to the number of cotyledons in the seedlings. Concepts of Biology 2013-04-25T00:00:00Z In five days, the “baby” cotyledon leaves were up, with the “true” notched tomato leaves following at day 10. Adventures in AeroGardening — tomatoes grown from the kitchen counter | Produced by Seattle Times Marketing 2023-01-27T05:00:00Z It typically grows there until the first true leaves appear, although robust growers may be ready for the next step when they still have only seed leaves, or cotyledons. Studying the flowers — knowing how (and when) to sow your seed collection 2023-01-18T05:00:00Z Flowering plants were previously classified by the number of seed leaves, or cotyledons, in their embryos. Miller & Levine Biology 2018-01-01T00:00:00Z Flowering plants are divided into two major groups, according to the structure of the cotyledons, pollen grains, and other structures. Fundamentals of Biology 2015-01-01T00:00:00Z The zygote develops into an embryo with a radicle, or small root, and one or two leaf-like organs called cotyledons. Concepts of Biology 2013-04-25T00:00:00Z In these cases the cotyledons are plane; but they may be folded upon themselves and round the radicle, as in Mustard, where they are conduplicate, thus o>>. The Manual of the Botany of the Northern United States Including the District East of the Mississippi and North of North Carolina and Tennessee 2012-04-12T02:00:30.140Z A plant which has no cotyledons, as the dodder and all flowerless plants. Webster's Unabridged Dictionary 2012-03-24T02:00:23.513Z The seeds are filled with the large embryo, the two cotyledons of which are variously folded. Encyclopaedia Britannica, 11th Edition, Volume 7, Slice 7 "Crocoite" to "Cuba" 2012-01-22T03:00:24.397Z The structure of the seed, the presence of two neck-cells in the archegonia, the late development of the embryo, the partially-fused cotyledons and certain anatomical characters, are features common to Ginkgo and the cycads. Encyclopaedia Britannica, 11th Edition, Volume 12, Slice 7 "Gyantse" to "Hallel" 2011-12-26T03:00:11.613Z Seed food reserves are stored outside the embryo, and the cotyledons serve as conduits to transmit the broken-down food reserves to the developing embryo. Concepts of Biology 2013-04-25T00:00:00Z Seeds flat or flattish, orbicular or oval; cotyledons accumbent or nearly so. The Manual of the Botany of the Northern United States Including the District East of the Mississippi and North of North Carolina and Tennessee 2012-04-12T02:00:30.140Z There is some difference of opinion as to which structure or structures represent the cotyledon. Encyclopaedia Britannica, 11th Edition, Volume 12, Slice 3 "Gordon, Lord George" to "Grasses" 2011-11-13T03:00:13.177Z In germination the cotyledons come above ground and form the first green leaves of the plant. Encyclopaedia Britannica, 11th Edition, Volume 7, Slice 7 "Crocoite" to "Cuba" 2012-01-22T03:00:24.397Z The bundles from the cotyledons pursue a direct course to the stele of the main axis, and do not assume the girdle-form characteristic of the adult plant. Encyclopaedia Britannica, 11th Edition, Volume 12, Slice 7 "Gyantse" to "Hallel" 2011-12-26T03:00:11.613Z Between the upper and the middle strata were sprouting nuts and seeds, with their blanched roots threaded downward into the rich dark mold, and the greening cotyledons curling upward toward light and warmth. Jungle Peace 2011-10-06T02:00:42.363Z Embryo large, with broad cotyledons.—A family with showy flowers, the types of which are the well-known Camellia and the more important Tea Plant,—represented in this country by the two following genera. The Manual of the Botany of the Northern United States Including the District East of the Mississippi and North of North Carolina and Tennessee 2012-04-12T02:00:30.140Z The epiblast has been regarded as representing a second cotyledon, but this is a very doubtful interpretation. Encyclopaedia Britannica, 11th Edition, Volume 12, Slice 3 "Gordon, Lord George" to "Grasses" 2011-11-13T03:00:13.177Z The embryo generally fills the seed, and the cotyledons are rolled or folded on each other. Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 7 "Geoponici" to "Germany" 2011-09-26T02:00:25.313Z The ripe albuminous seed contains a single embryo with two or more cotyledons. Encyclopaedia Britannica, 11th Edition, Volume 12, Slice 7 "Gyantse" to "Hallel" 2011-12-26T03:00:11.613Z The cotyledons usually form the greater part of the mature embryo, and this is remarkably well seen in such exalbuminous seeds as the bean and pea. Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 3 "Frost" to "Fyzabad" 2011-08-15T02:00:28.473Z Embryo large and straight in fleshy albumen; cotyledons flat.—Herbs, with sour watery juice, alternate or radical leaves, mostly of 3 obcordate leaflets, which close and droop at nightfall. The Manual of the Botany of the Northern United States Including the District East of the Mississippi and North of North Carolina and Tennessee 2012-04-12T02:00:30.140Z The seed germinates and thousands of cotyledon leaves appear like fairy umbrellas, from the waste of the dead leaves. A West Country Pilgrimage 2011-08-05T02:00:48.947Z The general character of the talamisan together with the presence of hypogeal cotyledons tends to the belief that this species has more or less united filaments and thus would belong to the first group. The Philippine Agricultural Review Vol. VIII, First Quarter, 1915 No. 1 2011-04-13T02:00:12.527Z My pansies and alyssum were up—at least I believed they were up, but I spent many minutes of each day kneeling by them and studying the physiognomy of their cotyledons. The Jonathan Papers The radicle r is folded on the edges of the cotyledons c which are accumbent. Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 3 "Frost" to "Fyzabad" 2011-08-15T02:00:28.473Z Embryo large, in fleshy albumen; cotyledons broad and thin. The Manual of the Botany of the Northern United States Including the District East of the Mississippi and North of North Carolina and Tennessee 2012-04-12T02:00:30.140Z Incumbent, leaning or resting upon; the cotyledons are incumbent when the back of one of them lies against the radicle, 128; the anthers are incumbent when turned or looking inwards. The Elements of Botany For Beginners and For Schools Lepidium sativum L. Seed reddish yellow to reddish brown, oval, slightly compressed, often nearly straight on one edge, usually showing two vertical grooves on each side, 2.5 mm. long, cotyledons incumbent. Seeds of Michigan Weeds Bulletin 260, Michigan State Agricultural College Experiment Station, Division of Botany, March, 1910 I do wish somebody would make a book with pictures of all the cotyledons of all the different plants. The Jonathan Papers The radicle and cotyledons are either straight or variously curved. Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 3 "Frost" to "Fyzabad" 2011-08-15T02:00:28.473Z Embryo large, with broad cotyledons, in sparing fleshy albumen.—Flowers often polygamous, sometimes diœcious. The Manual of the Botany of the Northern United States Including the District East of the Mississippi and North of North Carolina and Tennessee 2012-04-12T02:00:30.140Z When there is such a bud between the cotyledons in the seed or seedling it is called the Plumule. The Elements of Botany For Beginners and For Schools Em�bry-o, the little plant forming a part of the seed, usually consisting of caulicle, one or more cotyledons and a plumule. Seeds of Michigan Weeds Bulletin 260, Michigan State Agricultural College Experiment Station, Division of Botany, March, 1910 A grand division of the vegetable kingdom, founded on the plant having two cotyledons, or seed-lobes. Principles of Geology or, The Modern Changes of the Earth and its Inhabitants Considered as Illustrative of Geology In other divisions the radicle is folded in a spiral manner, and the cotyledons follow the same course. Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 3 "Frost" to "Fyzabad" 2011-08-15T02:00:28.473Z Embryo variously coiled or folded, with large and thin cotyledons.—Trees, or sometimes shrubs, with opposite palmately-lobed leaves, and small flowers. The Manual of the Botany of the Northern United States Including the District East of the Mississippi and North of North Carolina and Tennessee 2012-04-12T02:00:30.140Z The cotyledons are crumpled in the seed, and not easy to straighten out until they unfold themselves in germination. The Elements of Botany For Beginners and For Schools The seeds are angular and contain a thread-like spirally coiled embryo which bears no cotyledons. Encyclopaedia Britannica, 11th Edition, Volume 8, Slice 5 "Dinard" to "Dodsworth" Cuscuta has a thread-like, spirally twisted embryo with no trace of cotyledons. Encyclopaedia Britannica, 11th Edition, Volume 7, Slice 3 "Convention" to "Copyright" In many gymnosperms more than two cotyledons are present, and they are arranged in a whorl. Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 3 "Frost" to "Fyzabad" 2011-08-15T02:00:28.473Z Embryo large and straight, in scanty albumen, cotyledons broad and thin.—Upright shrubs, with opposite pinnate leaves of 3 or 5 serrate leaflets, and white flowers in drooping raceme-like clusters, terminating the branchlets. The Manual of the Botany of the Northern United States Including the District East of the Mississippi and North of North Carolina and Tennessee 2012-04-12T02:00:30.140Z Correspondingly, their caulicle does not lengthen to elevate them above the surface of the soil; the growth below the cotyledons is nearly all of root. The Elements of Botany For Beginners and For Schools When the two first leaves are fully developed the plants to be earthed up as high as the cotyledons. In-Door Gardening for Every Week in the Year Showing the Most Successful Treatment for all Plants Cultivated in the Greenhouse, Conservatory, Stove, Pit, Orchid, and Forcing-house First the shell, or outer husk, is dropped or cast off; then the cotyledons, those nurse leaves of the young plant; then the fruit falls, and at last the stalk and leaf. A Year in the Fields Within the cotyledons the primordial leaves are seen, constituting the plumule or first bud of the plant. Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 3 "Frost" to "Fyzabad" 2011-08-15T02:00:28.473Z Embryo straight; cotyledons very short.—Perennial smooth herbs, with entire leaves, and solitary flowers on long scape-like stems, which usually bear a single sessile leaf. The Manual of the Botany of the Northern United States Including the District East of the Mississippi and North of North Carolina and Tennessee 2012-04-12T02:00:30.140Z The cotyledons all the while remain below, in the husk of the fruit and seed, and perish when they have yielded up the store of food which they contained. The Elements of Botany For Beginners and For Schools This process of separating the cotyledons must be carefully conducted, one after another, until the last has been detached and the afterbirth comes freely out of the passages. Special Report on Diseases of Cattle The shell breaks, the cotyledons open, and the plant of faith is alive. Bunyan The radicle r is folded on the back of the cotyledons c, which are said to be incumbent. Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 3 "Frost" to "Fyzabad" 2011-08-15T02:00:28.473Z Embryo large and straight, in scanty albumen; cotyledons broad and flat. The Manual of the Botany of the Northern United States Including the District East of the Mississippi and North of North Carolina and Tennessee 2012-04-12T02:00:30.140Z Same opened out, to show the thick cotyledons and the little plumule or bud between them. The Elements of Botany For Beginners and For Schools The membrane of the uterus between the cotyledons also may show inflamed and necrotic patches. Special Report on Diseases of Cattle With it the bird readily breaks through the hard outer coat of most seeds and feeds upon the rich cotyledons that are enclosed within. The Meaning of Evolution Like leaves in the bud, cotyledons may be either applied directly to each other, or may be folded in various ways. Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 3 "Frost" to "Fyzabad" 2011-08-15T02:00:28.473Z The slender embryo therefore is horseshoe-shaped; cotyledons filiform.—Flowers white, in small and loose axillary panicles. The Manual of the Botany of the Northern United States Including the District East of the Mississippi and North of North Carolina and Tennessee 2012-04-12T02:00:30.140Z Seedling of same, showing the freshly expanded six cotyledons in a whorl, and the plumule just appearing. The Elements of Botany For Beginners and For Schools On the outer surface of this membrane are found the fetal placentul�, or cotyledons, which, through their attachment to the maternal cotyledons, furnish the fetus with the means of sustaining life. Special Report on Diseases of Cattle It is true that ants do sometimes destroy a few hills on certain soils, by sucking the cotyledons of the plant before it has attained any considerable size and strength. The Peanut Plant Its Cultivation And Uses In geranium the cotyledons are twisted and doubled; in convolvulus they are corrugated; and in the potato and in Bunias, they are spiral,—the same terms being applied as to the foliage leaves. Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 3 "Frost" to "Fyzabad" 2011-08-15T02:00:28.473Z Seeds spherical and cotyledons conduplicate, as in Brassica.—Annuals or biennials. The Manual of the Botany of the Northern United States Including the District East of the Mississippi and North of North Carolina and Tennessee 2012-04-12T02:00:30.140Z It would appear therefore that the cotyledon answers to a minute leaf rolled up, and that a chink through which the plumule grows out is a part of the inrolled edges. The Elements of Botany For Beginners and For Schools These inflammatory changes seem most intense in the cotyledons and result in the destruction of the minute structure of those bodies, and they appear swollen, pale, and soft. Special Report on Diseases of Cattle The cotyledons shown have three pairs of veins, which are slightly netted. All About Coffee Again, the cotyledons are conduplicate when the radicle is dorsal, and enclosed between their folds. Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 3 "Frost" to "Fyzabad" 2011-08-15T02:00:28.473Z Seeds anatropous, rather large, with a hard seed-coat, and a large and straight embryo nearly as long as the albumen; cotyledons flat.—Leaves alternate, with stipules. The Manual of the Botany of the Northern United States Including the District East of the Mississippi and North of North Carolina and Tennessee 2012-04-12T02:00:30.140Z There, in the seed, the cotyledon remains, imbibing nourishment from the softened albumen, and transmitting it to the growing root below and new-forming leaves above. The Elements of Botany For Beginners and For Schools The womb may be drawn out, but not until all the liquid has flowed out, and the fetal membranes must be separated from the natural cotyledons, one by one, and the membranes removed. Special Report on Diseases of Cattle The radicle is blunt and is about 3⁄4 mm in length, while the cotyledons are 1⁄2 mm long. All About Coffee In species of Streptocarpus the cotyledons are permanent, and act the part of leaves. Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 3 "Frost" to "Fyzabad" 2011-08-15T02:00:28.473Z Embryo straight, with broad cotyledons.—Shrubs or trees, with mostly pinnate leaves, the stems and often the leafstalks prickly. The Manual of the Botany of the Northern United States Including the District East of the Mississippi and North of North Carolina and Tennessee 2012-04-12T02:00:30.140Z There is sufficient nourishment in the cotyledons of a pea to make a very considerable growth before any actual foliage is required. The Elements of Botany For Beginners and For Schools In cutting, carefully avoid the cotyledons, which may be felt as hard masses inside. Special Report on Diseases of Cattle Seed large, two to four-lobed, cotyledons corrugated, oily, without endosperm. The Pecan and its Culture In the figure this narrowed portion is slightly separated from the groove; c, two rudimentary cotyledons. Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 3 "Frost" to "Fyzabad" 2011-08-15T02:00:28.473Z Flowers perfect; nutlets and seeds not furrowed; cotyledons flat, thick; rhaphe lateral. The Manual of the Botany of the Northern United States Including the District East of the Mississippi and North of North Carolina and Tennessee 2012-04-12T02:00:30.140Z Beginning germination of the Beech, showing the plumule growing before the cotyledons have opened or the root has scarcely formed. The Elements of Botany For Beginners and For Schools The relation of the fetal and maternal cotyledons to each other is illustrated on the following Plate. Special Report on Diseases of Cattle The palmate form of the cotyledons of the genus Pinus is particularly conspicuous in those of P. pinea. Scientific American Supplement, No. 488, May 9, 1885 The lamina of the cotyledon is not developed. Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 3 "Frost" to "Fyzabad" 2011-08-15T02:00:28.473Z Seeds oblong or elliptical, very small, wingless, in one row; cotyledons often more or less oblique. The Manual of the Botany of the Northern United States Including the District East of the Mississippi and North of North Carolina and Tennessee 2012-04-12T02:00:30.140Z The smallest, that of the Peony, is still large enough to be seen with a hand magnifying glass, and even its cotyledons may be discerned by the aid of a simple stage microscope. The Elements of Botany For Beginners and For Schools If carefully conducted, so as not to tear the cotyledons of the womb, the operation is eminently successful; the cow suffers little, and the straining roused by the manipulations soon subsides. Special Report on Diseases of Cattle The cross-section of a cotyledon is, therefore, a triangle whose angles vary with the number composing the fascicle. The Genus Pinus This by some was considered the rudimentary second cotyledon; but is now generally regarded as an outgrowth of the sheath of the true cotyledon. Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 3 "Frost" to "Fyzabad" 2011-08-15T02:00:28.473Z Embryo curved or convolute, rarely straight; cotyledons thick and fleshy.—Leaves alternate or sometimes opposite, without stipules, mostly compound. The Manual of the Botany of the Northern United States Including the District East of the Mississippi and North of North Carolina and Tennessee 2012-04-12T02:00:30.140Z A grain cut through the middle in the opposite direction, dividing the embryo through its thick cotyledon and its plumule, the latter consisting of two leaves, one enclosing the other. The Elements of Botany For Beginners and For Schools Each encloses a seed, hairy, albuminous with straight embryo and flattened cotyledons. The Medicinal Plants of the Philippines Sections from fascicles of 10 and of 5 cotyledons are shown in figs. The Genus Pinus It has been already stated that the radicle of the embryo is directed to the micropyle, and the cotyledons to the chalaza. Encyclopaedia Britannica, 11th Edition, Volume 11, Slice 3 "Frost" to "Fyzabad" 2011-08-15T02:00:28.473Z Embryo coiled or folded; the cotyledons long and thin.—Leaves opposite, simple or compound. The Manual of the Botany of the Northern United States Including the District East of the Mississippi and North of North Carolina and Tennessee 2012-04-12T02:00:30.140Z Indeed, the earliest growth which carries the very short caulicle out of the shell comes from the formation of foot-stalks to the cotyledons; above these develops the strong plumule, below grows the stout root. The Elements of Botany For Beginners and For Schools However, the major portion of the filling, which consists in the thickening of the cotyledons, takes place late in the season, and only a month or a little more before the nuts mature. Northern Nut Growers Association Incorporated 39th Annual Report at Norris, Tenn. September 13-15 1948 Apart from this difference cotyledons are much alike. The Genus Pinus The nitrogen of the testa, or covering of the seeds, will hardly be so assimilable as that which exists in their cotyledons. The Stock-Feeder's Manual the chemistry of food in relation to the breeding and feeding of live stock Shrubs with opposite entire leaves, no stipules, the sepals and petals similar and indefinite, the anthers adnate and extrorse, and the cotyledons convolute; the fruit like a rose-hip. The Manual of the Botany of the Northern United States Including the District East of the Mississippi and North of North Carolina and Tennessee 2012-04-12T02:00:30.140Z Half of an acorn, cut lengthwise, filled by the very thick cotyledons, the base of which encloses the minute caulicle. The Elements of Botany For Beginners and For Schools In such case, the lobes of the cotyledons may not attain the full length of the seed coat, or pellicle, which surrounds them. Northern Nut Growers Association Incorporated 39th Annual Report at Norris, Tenn. September 13-15 1948 The seed of Pinus contains an embryo, with the cotyledons clearly defined, embedded in albumen, which is protected by a bony testa with an external membranous spermoderm, produced, in most species, into an effective wing. The Genus Pinus I love the flowers, and I like to paint them and learn their English names, but I don't care in the least if their stamens are hypogynous or their cotyledons induplicate! The Nicest Girl in the School A Story of School Life Embryo with a single cotyledon and the early leaves always alternate. The Manual of the Botany of the Northern United States Including the District East of the Mississippi and North of North Carolina and Tennessee 2012-04-12T02:00:30.140Z Such thick cotyledons never separate; indeed, they sometimes grow together by some part of their contiguous faces; so that the germination seems to proceed from a solid bulb-like mass. The Elements of Botany For Beginners and For Schools Growth in length of the cotyledons may be arrested by unfavorable nutritional conditions during the time of elongation. Northern Nut Growers Association Incorporated 39th Annual Report at Norris, Tenn. September 13-15 1948 The scutellum is considered to represent the first leaf or cotyledon. A Handbook of Some South Indian Grasses I have met with corresponding instances in Antirrhinum majus and in Cratægus oxyacantha, in the latter case complicated with the partial atrophy of one of the four cotyledons. Vegetable Teratology An Account of the Principal Deviations from the Usual Construction of Plants Seeds with little albumen; embryo curved, the leafy cotyledons variously doubled up.—Mucilaginous, innocent plants, with tough bark and palmately-veined leaves. The Manual of the Botany of the Northern United States Including the District East of the Mississippi and North of North Carolina and Tennessee 2012-04-12T02:00:30.140Z Embryo taken out whole and unfolded; the broad and very thin cotyledons notched at summit; the caulicle below. The Elements of Botany For Beginners and For Schools After the cotyledons have attained full length, growth in thickness begins in the area nearest the epicotyl and proceeds toward the margins. Northern Nut Growers Association Incorporated 39th Annual Report at Norris, Tenn. September 13-15 1948 Where the cotyledons are broken off, the so-called crown of the walnut, two rough places appear, nearly opposite on the stem. Northern Nut Growers Association Report of the Proceedings at the Thirty-Eighth Annual Meeting Guelph, Ontario, September 3, 4, 5, 1947 It is necessary to distinguish between such cases and the fallacious appearances arising from a division of the cotyledons. Vegetable Teratology An Account of the Principal Deviations from the Usual Construction of Plants Embryo straight, cotyledons very thick, radicle very short.—Low tender annuals, with alternate pinnate leaves and no stipules. The Manual of the Botany of the Northern United States Including the District East of the Mississippi and North of North Carolina and Tennessee 2012-04-12T02:00:30.140Z The end which almost touches the seed coat is caulicle, the other end belongs to the solitary cotyledon. The Elements of Botany For Beginners and For Schools Leaves on the primary axis all compound; 1 to 4 pairs of opposite or subopposite reduced scales or buds sometimes present on the lower axis but above the cotyledons. Northern Nut Growers Association Thirty-Fourth Annual Report 1943 The pease, when fully ripe, are round and plump, cream-colored, white towards the eye and at the union of the cotyledons, and measure nearly a fourth of an inch in diameter. The Field and Garden Vegetables of America Containing Full Descriptions of Nearly Eleven Hundred Species and Varietes; With Directions for Propagation, Culture and Use. In these cases one almond encloses within its cotyledons a second embryo, and this, again, in some instances, a third, the little plants being thus packed like so many boxes one within the other. Vegetable Teratology An Account of the Principal Deviations from the Usual Construction of Plants Embryo in the axis of fleshy albumen; cotyledons minute. The Manual of the Botany of the Northern United States Including the District East of the Mississippi and North of North Carolina and Tennessee 2012-04-12T02:00:30.140Z Germinating Onion, more advanced, the chink at base of cotyledon opening for the protrusion of the plumule, consisting of a thread-shaped leaf. The Elements of Botany For Beginners and For Schools In addition, one or more pairs of minute simple scales or buds occur on the lower part of the stem but above the cotyledons. Northern Nut Growers Association Thirty-Fourth Annual Report 1943 Out of this comes heroism in all its shapes; here the enterprises that overshadow half the planet, when full grown, lie, tender, in their cotyledons. The Atlantic Monthly, Volume 2, No. 14, December 1858 Generally it does not give origin to shoots or leaves other than the seed-leaves, but occasionally shoots may be seen projecting from it below the level of the cotyledons. Vegetable Teratology An Account of the Principal Deviations from the Usual Construction of Plants Embryo with a pair of opposite cotyledons, or in Subclass II. often three or more in a whorl. The Manual of the Botany of the Northern United States Including the District East of the Mississippi and North of North Carolina and Tennessee 2012-04-12T02:00:30.140Z Embryo of Calycanthus; upper part cut away, to show the convolute cotyledons. The Elements of Botany For Beginners and For Schools If the primary axis is injured secondary shoots may arise from the axils of the cotyledons. Northern Nut Growers Association Thirty-Fourth Annual Report 1943 As their name indicates, there is but one cotyledon or seed leaf, and the leaves from the first are alternate. Elements of Structural and Systematic Botany For High Schools and Elementary College Courses The cotyledons are very uniform in shape in each plant, and are scarcely ever subject to variation. Vegetable Teratology An Account of the Principal Deviations from the Usual Construction of Plants Embryo with a pair of opposite cotyledons, or rarely several in a whorl. The Manual of the Botany of the Northern United States Including the District East of the Mississippi and North of North Carolina and Tennessee 2012-04-12T02:00:30.140Z In one very natural family, the Crucifer�, two different modes prevail in the way the two cotyledons are brought round against the radicle. The Elements of Botany For Beginners and For Schools Scales or buds wanting between the lowest compound leaves and the leaves and the cotyledons J. sieboldiana 2. Northern Nut Growers Association Thirty-Fourth Annual Report 1943 The second sub-class of the angiosperms, the dicotyledons, receive their name from the two opposite seed leaves or cotyledons with which the young plant is furnished. Elements of Structural and Systematic Botany For High Schools and Elementary College Courses There are cases among flowering plants where the embryo is homogeneous in its structure, there are others in which the number of the cotyledons is more than two. Vegetable Teratology An Account of the Principal Deviations from the Usual Construction of Plants Radicle hardly any; cotyledons thick and fleshy, enclosing a well-developed plumule.—Flowers axillary, solitary. The Manual of the Botany of the Northern United States Including the District East of the Mississippi and North of North Carolina and Tennessee 2012-04-12T02:00:30.140Z Seed of Bitter Cress, Barbarea, cut across to show the accumbent cotyledons. The Elements of Botany For Beginners and For Schools Walnut cake, after expressing out the oil from the kernels, is a good food for cattle, these kernels being the crumpled cotyledons or seed leaves. Herbal Simples Approved for Modern Uses of Cure L, an embryo removed from a nearly ripe seed, and spread out; one of the cotyledons has been partially removed, × 1. Elements of Structural and Systematic Botany For High Schools and Elementary College Courses Thus, in some seeds of Cola acuminata the cotyledons vary in number from two to five. Vegetable Teratology An Account of the Principal Deviations from the Usual Construction of Plants Embryo like that of Nymphæa on a large scale; cotyledons thick and fleshy, enclosing a plumule of 1 or 2 well-formed young leaves, enclosed in a delicate stipule-like sheath. The Manual of the Botany of the Northern United States Including the District East of the Mississippi and North of North Carolina and Tennessee 2012-04-12T02:00:30.140Z Incumbent, or with the plane of the cotyledons brought up in the opposite direction, so that the back of one of them lies against the radicle, as shown in Fig. The Elements of Botany For Beginners and For Schools The two cotyledons, which form the seed, are not brittle when found in nature in the pod. Cocoa and Chocolate Their History from Plantation to Consumer E, the embryo, with one of the cotyledons removed, × 2. Elements of Structural and Systematic Botany For High Schools and Elementary College Courses I have not been able to ascertain precisely whether this multiplication of the cotyledons is characteristic of all the seeds of particular trees, or whether some only are thus affected. Vegetable Teratology An Account of the Principal Deviations from the Usual Construction of Plants Seeds in 2 rows in each cell, rounded, broadly winged; cotyledons accumbent; radicle short.—A low annual, with once or twice pinnatifid leaves and leafy-bracteate racemes of yellow flowers. The Manual of the Botany of the Northern United States Including the District East of the Mississippi and North of North Carolina and Tennessee 2012-04-12T02:00:30.140Z Seed of a Sisymbrium, cut across to show the incumbent cotyledons. The Elements of Botany For Beginners and For Schools After roasting, the shell is brittle and quite free from the cotyledons or kernel. Cocoa and Chocolate Their History from Plantation to Consumer The ants enjoyed the sprouting cotyledons of all but one. Northern Nut Growers Association, report of the proceedings at the eighth annual meeting Stamford, Connecticut, September 5 and 6, 1917 Some fruits that I examined bore out the latter view, as in the same pod were seeds with two, three, and four cotyledons respectively. Vegetable Teratology An Account of the Principal Deviations from the Usual Construction of Plants Seeds in one row in each cell, orbicular or nearly so, more or less wing-margined; cotyledons strictly accumbent. The Manual of the Botany of the Northern United States Including the District East of the Mississippi and North of North Carolina and Tennessee 2012-04-12T02:00:30.140Z Similar section through a seed turned edgewise, showing the thickness of the cotyledons, and the minute plumule between them, i. e. the minute bud on the upper end of the caulicle. The Elements of Botany For Beginners and For Schools It is said to be a seedling from S. Nepalensis crossed by S. cotyledon or S. pyramidalis, but, as the cross was accidental, there must be some uncertainty; both parents are evidently incrusted forms. Hardy Perennials and Old Fashioned Flowers Describing the Most Desirable Plants, for Borders, Rockeries, and Shrubberies. The grub, upon hatching out, being as yet incapable of attacking the firm substance of the cotyledons, masticates the delicate felt-like layer at the base of the cup and is nourished by its juices. Social Life in the Insect World This fusion seems frequently to accompany increase in the number of cotyledons. Vegetable Teratology An Account of the Principal Deviations from the Usual Construction of Plants Embryo long and slender, straightish or curved, in mealy albumen; cotyledons narrow.—Leaves simple and mostly entire, the lower usually opposite, and the upper alternate. The Manual of the Botany of the Northern United States Including the District East of the Mississippi and North of North Carolina and Tennessee 2012-04-12T02:00:30.140Z Recently it has been named Hypocotyle; which signifies something below the cotyledons, without pronouncing what its nature is. The Elements of Botany For Beginners and For Schools To show the use of cotyledons 83 45. The First Book of Farming Before setting to work on the cotyledons the grub does, in fact, commence upon the contents and walls of this tiny passage. Social Life in the Insect World According to this gentleman, those seedlings which produce three cotyledons in a whorl in place of two, form double flowers. Vegetable Teratology An Account of the Principal Deviations from the Usual Construction of Plants Embryo straightish, with a short radicle, and thin longitudinally plaited cotyledons.—Shrubs or small trees, with large and showy white flowers on axillary peduncles. The Manual of the Botany of the Northern United States Including the District East of the Mississippi and North of North Carolina and Tennessee 2012-04-12T02:00:30.140Z This deposit of food thickens the cotyledons, and renders them less and less leaf-like in proportion to its amount. The Elements of Botany For Beginners and For Schools The part bearing the tiny leaves was formerly, and is sometimes now, called the plumule, but is generally called the epicotyl, because it grows above or upon the cotyledons. The First Book of Farming Above this is the tougher nutriment of the cotyledons. Social Life in the Insect World We shall not always be rank with noisome weeds and thistles; here and there, the better thought is swelling toward the germination; the cotyledons of a fairer hope are rising through the mould. The Other Girls Seed anatropous, erect, filled by the large embryo with its hemispherical fleshy cotyledons.—A small and inconspicuous annual, with minute solitary flowers on axillary peduncles. The Manual of the Botany of the Northern United States Including the District East of the Mississippi and North of North Carolina and Tennessee 2012-04-12T02:00:30.140Z Germinating Embryo supplied by its own Store of Nourishment, i. e. the store in the cotyledons. The Elements of Botany For Beginners and For Schools The round pointed projection was formerly called the radicle, but is now spoken of as the hypocotyl, because it grows below or under the cotyledons. The First Book of Farming The peopled acorns remain on the oak, held in their cups as though nothing had occurred to the detriment of the cotyledons. Social Life in the Insect World The cotyledons are tender and tasty, perhaps sugary from Nature's process of malting; and while the seed-leaf is assailable the Haltica makes the best of the shining hour. The Culture of Vegetables and Flowers From Seeds and Roots 16th Edition Seeds anatropous, mostly single in each cell, large and flat, with a smooth coriaceous integument; the embryo shorter than the hard albumen, with a long radicle and flat cotyledons. The Manual of the Botany of the Northern United States Including the District East of the Mississippi and North of North Carolina and Tennessee 2012-04-12T02:00:30.140Z Evidently here the germinating embryo is principally fed by one of the leaf-like cotyledons, the other being out of contact with the supply. The Elements of Botany For Beginners and For Schools This is the one cotyledon of the corn. The First Book of Farming This perisperm covers an exalbuminous embryo formed almost entirely of two thick, greenish yellow cotyledons having a strong taste of legumine. Scientific American Supplement, No. 613, October 1, 1887 And though on the separation of the cotyledons of ruminating animals no blood is effused, yet this is owing clearly to the greater power of contraction of their uterine lacun� or alveoli. Zoonomia, Vol. I Or, the Laws of Organic Life Embryo nearly the length of the albumen; radicle slender, as long as or longer than the flat cotyledons. The Manual of the Botany of the Northern United States Including the District East of the Mississippi and North of North Carolina and Tennessee 2012-04-12T02:00:30.140Z Embryo detached; showing the very broad and leaf-like cotyledons, applied face to face, and the pair incurved. The Elements of Botany For Beginners and For Schools Besides this will be found quite a mass of starchy material packed in the coverings of the kernel and in close contact with one side of the cotyledon. The First Book of Farming When examined under the microscope, these cotyledons, the alimentary part of the seed, have the appearance represented in Fig. Scientific American Supplement, No. 613, October 1, 1887 There seems however to be a reservoir of nutriment prepared for some seeds besides their cotyledons or seed-leaves, which may be supposed in some measure analogous to the yolk of the egg. Zoonomia, Vol. I Or, the Laws of Organic Life Embryo straight and axile, with foliaceous cotyledons.—Annuals or perennials, with radical or alternate or whorled entire leaves, without stipules. The Manual of the Botany of the Northern United States Including the District East of the Mississippi and North of North Carolina and Tennessee 2012-04-12T02:00:30.140Z Embryo of Abronia umbellata; one of the cotyledons very small. The Elements of Botany For Beginners and For Schools Within the cotyledon will be found a little growing shoot pointed toward the top of the kernel. The First Book of Farming I think that botanists have called it Saxifraga cotyledon; yet, in spite of its long name, it is beautiful and poetic. Sketches and Studies in Italy and Greece, First Series The young plant has two seed-leaves or "cotyledons," and these plants are therefore called "Dicotyledons." The Ancient Life History of the Earth A Comprehensive Outline of the Principles and Leading Facts of Palæontological Science Embryo thick, the cotyledons incumbent upon the radicle.—Low saline plants, with succulent leafless jointed stems, and opposite branches; the flower-bearing branchlets forming the spikes. The Manual of the Botany of the Northern United States Including the District East of the Mississippi and North of North Carolina and Tennessee 2012-04-12T02:00:30.140Z Polycotyledonous is a name employed for the less usual case in which there are more than two cotyledons. The Elements of Botany For Beginners and For Schools The pea cotyledons were left down in the soil, the epicotyl alone pushing up to the surface. The First Book of Farming With the larger cotyledon the crying disproportion between the number of eggs and the available provision disappears. A Book of Exposition Some plantlets, as they develop and start to push above the ground, bear along the cotyledon. The Library of Work and Play: Gardening and Farming. Embryo placed in a groove on the outside of the albumen and curved half-way around it; the radicle and usually the cotyledons slender.—Pedicels jointed. The Manual of the Botany of the Northern United States Including the District East of the Mississippi and North of North Carolina and Tennessee 2012-04-12T02:00:30.140Z This occurs in all Pines, the number of cotyledons varying from three to twelve; in Fig. The Elements of Botany For Beginners and For Schools Large, strong seeds like corn, peas, etc., which do not lift their cotyledons above the surface, can be planted with safety at a depth of from one to four or five inches. The First Book of Farming In dry seasons the crop is often destroyed by the ravages of a small beetle, which perforates the cotyledons of the plants, and destroys the crop on whole fields in a few hours. The Botanist's Companion, Volume II It is called a cotyledon if there is but one portion, cotyledons if two. The Library of Work and Play: Gardening and Farming. Embryo small, at the apex of copious albumen; radicle directed upward; cotyledons cylindrical. The Manual of the Botany of the Northern United States Including the District East of the Mississippi and North of North Carolina and Tennessee 2012-04-12T02:00:30.140Z When there are only three cotyledons, they divide the space equally, are one third of the circle apart. The Elements of Botany For Beginners and For Schools Of the beans, No. 6 succeeded in pulling the cotyledons to the surface, and has made a good plant. The First Book of Farming Where the bare rock showed itself, yellow sedum spread its gold, and in the little clefts stood stalks of cotyledon, now turning brown. Wanderings by southern waters, eastern Aquitaine A few plants that bear cones like the pines have several cotyledons. The Library of Work and Play: Gardening and Farming. Albumen none; embryo straight; the cotyledons large.—Flowers polygamous, purplish or yellowish, in lateral clusters, in our species preceding the leaves, which are strongly straight-veined, short-petioled, and oblique or unequally somewhat heart-shaped at base. The Manual of the Botany of the Northern United States Including the District East of the Mississippi and North of North Carolina and Tennessee 2012-04-12T02:00:30.140Z But germination plainly shows that all except the lower end of it is cotyledon. The Elements of Botany For Beginners and For Schools Seeds which raise their cotyledons above the soil should not be planted as deep as those which do not. The First Book of Farming The leaves are commonly netted-veined, and the number of cotyledons is two, or, very rarely, several in a whorl. The Gutenberg Webster's Unabridged Dictionary Section D and E But most plants have either one or two cotyledons. The Library of Work and Play: Gardening and Farming. Embryo with a single cotyledon, and the leaves of the plumule alternate. The Manual of the Botany of the Northern United States Including the District East of the Mississippi and North of North Carolina and Tennessee 2012-04-12T02:00:30.140Z The larger part of it is the cotyledon, thickish, its edges involute, and its back in contact with the albumen; partly enclosed by it is the well-developed plumule or bud which is to grow. The Elements of Botany For Beginners and For Schools The name is derived from the absence of a seed-leaf or cotyledon. The Project Gutenberg Encyclopedia Volume 1 of 28 The leaves of the endogens have, usually, parallel veins, their flowers are mostly in three, or some multiple of three, parts, and their embryos have but a single cotyledon, with the first leaves alternate. The Gutenberg Webster's Unabridged Dictionary Section D and E See the bean plantlet, big, sturdy, fellow, is still clinging to its seed leaves or cotyledons, its baby nourishment. The Library of Work and Play: Gardening and Farming. Embryo terete, in the axis of copious albumen, with a slender inferior radicle and very small cotyledons. The Manual of the Botany of the Northern United States Including the District East of the Mississippi and North of North Carolina and Tennessee 2012-04-12T02:00:30.140Z So, also, the seed-leaves or cotyledons are commonly used for storage. The Elements of Botany For Beginners and For Schools Flowering plants bear a seed containing an embryo, with usually one or two cotyledons, or seed-leaves; while in flowerless plants there is no seed and therefore no true cotyledon. The Project Gutenberg Encyclopedia Volume 1 of 28 They said "cotyledon," and "syngenesious," and "coniferous," and such words, remarkably well, considering they did not care two straws about them. How to Do It In germination the two fleshy cotyledons of the Gingkgo remain within the shell, leaving the three-sided plumule to pass upward; the young stem bears its leaves in threes. Scientific American Supplement, No. 360, November 25, 1882 Embryo large, with broad foliaceous cotyledons in thin albumen.—Perennial upright herbs, with thick and deep roots; peduncles terminal or lateral and between the usually opposite petioles, bearing simple many-flowered umbels, in summer. The Manual of the Botany of the Northern United States Including the District East of the Mississippi and North of North Carolina and Tennessee 2012-04-12T02:00:30.140Z Plumule, the bud or first shoot of a germinating plantlet above the cotyledons, 13. The Elements of Botany For Beginners and For Schools The maternal cotyledons or "buttons" form appendages or thickened points that become greatly enlarged in the pregnant animal. Common Diseases of Farm Animals When a seed of Cuscuta, germinates, no cotyledons are to be distinguished. Scientific American Supplement, No. 430, March 29, 1884 This seedling in the various species of clover usually begins with a first leaf above the cotyledons of a different structure from those that follow. Species and Varieties, Their Origin by Mutation Many seeds, from the decomposition of the oil contained in the cotyledons, lose the faculty of germination before the rainy season, in which the ligneous integument of the pericarp opens by the effect of putrefaction. Personal Narrative of Travels to the Equinoctial Regions of America, During the Year 1799-1804 — Volume 2 Primordial, earliest formed; primordial leaves are the first after the cotyledons. The Elements of Botany For Beginners and For Schools In the Sunflower the true leaves are nearly the same shape as the cotyledons, so that this is an especially good illustration for the purpose. Outlines of Lessons in Botany, Part I; from Seed to Leaf Many are of opinion that even the placenta of the human fetus, and cotyledons of quadrupeds, are respiratory organs rather than nutritious ones. The Botanic Garden. Part II. Containing the Loves of the Plants. a Poem. With Philosophical Notes. Among many thousands of normal seedlings I found two with three and one with four cotyledons. Species and Varieties, Their Origin by Mutation "A ____ leaf is that which is immediately developed from the cotyledon." The Century Vocabulary Builder The Conifers are not dicotyledons: their seeds contain numerous cotyledons, up to twenty in number, and the whole plant, and especially the reproductive system, belongs to a lower stage of development. The Antiquity of Man The cotyledons in the first make apparently an unsuccessful effort to become leaves, which the second give up altogether. Outlines of Lessons in Botany, Part I; from Seed to Leaf The cotyledons appear on the eighth day, and the young plants are covered with large leaves of heliconia and plantain, and shelter them from the direct action of the sun. Personal Narrative of Travels to the Equinoctial Regions of America, During the Year 1799-1804 — Volume 1 Those that display their cotyledons on a sunny day will be able to begin at once with the production of organic food. Species and Varieties, Their Origin by Mutation Of the eleven seedlings raised, three had the edges of their cotyledons slightly browned, as if scorched; and the cotyledons of one grew into a curious indented shape. Insectivorous Plants The cotyledons which are formed beneath the closed seed-sheath are charged, so to speak, with only a crude sap; they are scarcely and but rudely organized and quite undeveloped. Man or Matter These last can be again divided into those in which the cotyledons come up into the air and those where they remain in the ground. Outlines of Lessons in Botany, Part I; from Seed to Leaf The flattened hypocotyl is fleshy, enlarged in the upper part, and bears two rudimentary cotyledons. The Power of Movement in Plants For brevity's sake all these cleft and ternate, double cleft and quaternate cotyledons and even the higher grades are combined under one common name and indicated as tricotyls. Species and Varieties, Their Origin by Mutation Two mustard seeds germinated; but their cotyledons were marked with brown patches and their radicles deformed. Insectivorous Plants Its hard covering, by roasting, became very brittle; and I pounded the cotyledons, and boiled them for several hours. Journal of an Overland Expedition in Australia : from Moreton Bay to Port Essington, a distance of upwards of 3000 miles, during the years 1844-1845 In the latter the cotyledons are so heavily gorged with nourishment that they never become of any use as leaves. Outlines of Lessons in Botany, Part I; from Seed to Leaf It breaks through the ground in an arched form, with the rudimentary cotyledons closed or in contact. The Power of Movement in Plants This is of some importance, as the young plants when unfolding their cotyledons and primary leaves, may be distinguished by this means from the seedlings of the white flowered species. Species and Varieties, Their Origin by Mutation This seedling had an extremely short, crooked, diseased, radicle, with no absorbent hairs; and the cotyledons were oddly mottled with purple, with the edges blackened and partly withered. Insectivorous Plants Variegation, however, appears still more frequently in plants produced from seed; even the cotyledons or seed-leaves being thus affected. The Variation of Animals and Plants under Domestication — Volume 1 Vertical section, dividing the embryo, a, caulicle: b, cotyledon; c, plumule. Outlines of Lessons in Botany, Part I; from Seed to Leaf The hypocotyl of a seedling was secured to a little stick; it bore nine in appearance distinct cotyledons, arranged in a circle. The Power of Movement in Plants These effects are of a cumulative nature as the young plants must profit by every hour of sunshine, according to the size of the cotyledons. Species and Varieties, Their Origin by Mutation With Coffea arabica also seeds including two embryos are not very rare; but I have not yet observed whether in this case the cotyledons be inequal. More Letters of Charles Darwin — Volume 2 Does a bud ever produce cotyledons or embryonic leaves? More Letters of Charles Darwin — Volume 1 Closely applied to one side of this, so closely that it is difficult to separate it perfectly, is the single cotyledon. Outlines of Lessons in Botany, Part I; from Seed to Leaf Abronia has only a single fully developed cotyledon, but in this case it is the hypocotyl which first emerges and is arched. The Power of Movement in Plants The whorl may even consist of four, and in rare cases of five or more cotyledons. Species and Varieties, Their Origin by Mutation I know not in the least what plants have large cotyledons. More Letters of Charles Darwin — Volume 2 The two or three, or even more, internodes which are first formed above the cotyledons, or above the root-stock of a perennial plant, do not move; they can support themselves, and nothing superfluous is granted. The Movements and Habits of Climbing Plants There is a line down the middle, and, if we carefully bend back the edges of the cotyledon, it splits along this line, showing the plumule and caulicle within. Outlines of Lessons in Botany, Part I; from Seed to Leaf A glass filament with a bead at its end was affixed to the basal half or leg, just above the hypogean cotyledons, which were again almost surrounded by loose earth. The Power of Movement in Plants Cleft cotyledons are also to be met with, and the fissure may extend varying distances from the tips. Species and Varieties, Their Origin by Mutation A line joining the two cotyledons stood facing a north-east window, and the day was uniformly cloudy. More Letters of Charles Darwin — Volume 2 The leaves succeeding the cotyledons being almost clover-like in shape, seems to me feebly analogous to embryonic resemblances in young animals, as, for instance, the young lion being striped. Life and Letters of Charles Darwin — Volume 1 In Wheat and Oats the cotyledon can be easily seen in the largest seedlings by pulling off the dry husk of the grain. Outlines of Lessons in Botany, Part I; from Seed to Leaf Therefore the cotyledons certainly circumnutated, though the chief movement was up and down in a vertical plane. The Power of Movement in Plants As soon as they display their cotyledons, they are counted, and the number is the criterion of the parent-plant. Species and Varieties, Their Origin by Mutation A bristle was gummed to one cotyledon, and beyond it a triangular bit of card was fixed, and in front a vertical glass. More Letters of Charles Darwin — Volume 2 Thus the main divisions of flowering plants are founded on differences in the embryo—on the number and position of the cotyledons, and on the mode of development of the plumule and radicle. The Origin of Species by means of Natural Selection, 6th Edition How many cotyledons have Corn, Wheat, and Oats? Outlines of Lessons in Botany, Part I; from Seed to Leaf Under these circumstances it was interesting to observe how rapidly the circumnutating apex of a cotyledon passed across the divisions of the micrometer. The Power of Movement in Plants The first organs of its upward growth are known by the name of cotyledons; they have also been called seed-leaves. A History of Science — Volume 4 The cotyledon of Primula sinensis moved in closely analogous manner, as do those of a Cassia. More Letters of Charles Darwin — Volume 2 The natural system, as finally propounded by them, is based on the number of cotyledons, the structure of the seed, and the insertion of the stamens. A History of Science — Volume 2 Fleshy Roots.—The scholars are already familiar with the storing of food for the seedling in or around the cotyledons, and will readily understand that these roots are storehouses of food for the plant. Outlines of Lessons in Botany, Part I; from Seed to Leaf We shall recur to the nocturnal or sleep-movements of the cotyledons in a future chapter. The Power of Movement in Plants On the other hand, we observe that even the cotyledons which are most like a leaf when compared with the following leaves of the stalk are always more undeveloped or less developed. A History of Science — Volume 4 So it is with the cotyledons of the cabbage, and therefore I am very curious to ascertain how far this is general. More Letters of Charles Darwin — Volume 2 The former sees a tree in all its glory, where the latter sees an exogen with a pair of cotyledons. The Unseen World and Other Essays We have studied leaves as cotyledons, bud-scales, etc., but when we speak of leaves, we do not think of these adapted forms, but of the green foliage of the plant. Outlines of Lessons in Botany, Part I; from Seed to Leaf The longer axes of all were oblique to a line joining the opposite cotyledons. The Power of Movement in Plants Already in connection with the cotyledons above, we noticed a similar working of nature. A History of Science — Volume 4 Perhaps you may like to see a rough copy of the tracing of movements of one of the cotyledons of red cabbage, and you can throw it into the fire. More Letters of Charles Darwin — Volume 2 Would it have force to develop and open its young cotyledons, Could it compare, and reflect, and examine one thing with another? Amours De Voyage The movements of the cotyledons of two seedlings were observed; one facing a north-east window, and the other so feebly illuminated from above us as to be almost in darkness. The Power of Movement in Plants In rarely or never becoming perfectly straight, these cotyledons differ remarkably from the ultimate condition of the arched hypocotyls or epicotyls of dicotyledons. The Power of Movement in Plants A few or many of the next following leaves are often already present in the seed, and lie enclosed between the cotyledons; in their folded state they are known by the name of plumules. A History of Science — Volume 4 Hence I expect to find such movements very general with cotyledons, and I am inclined to look at them as the foundation for all the other adaptive movements of leaves. More Letters of Charles Darwin — Volume 2 The cotyledons of several other species of Ipomoea likewise sink downwards late in the evening. The Power of Movement in Plants The apex of one of the cotyledons crossed rather obliquely four divisions in 13 minutes; it was also sinking, as shown by getting out of focus. The Power of Movement in Plants Allium cepa: circumnutation of basal half of arched cotyledon, traced in darkness on horizontal glass, from 8.15 A.M. to 10 P.M. The Power of Movement in Plants Their form, as compared with the cotyledons and the following leaves, varies in different plants. A History of Science — Volume 4 Might not the inequality of the cotyledons of Citrus and of Pachira be attributed to the pressure, which the several embryos enclosed in the same seed exert upon each other? More Letters of Charles Darwin — Volume 2 Filaments were therefore fixed horizontally to two hypocotyls close beneath the petioles of their cotyledons. The Power of Movement in Plants After 3 h. the cotyledons were doubtfully curved towards the light, and after 7 h. The Power of Movement in Plants Phalaris Canariensis: circumnutation of a cotyledon, with a mark placed below the apex, traced on a horizontal glass, from 8.35 A.M. The Power of Movement in Plants Their chief point of variance, however, from the cotyledons is that they are flat, delicate, and formed like real leaves generally. A History of Science — Volume 4 The hypocotyl may therefore be said to sacrifice itself for the good of the cotyledons, or rather of the whole plant. The Power of Movement in Plants The basal edges could be pressed into close contact with the cotyledons; though this again required care to prevent injuring them. The Power of Movement in Plants It should be kept in mind that young cotyledons were selected for trial, and that these when not interfered with become bowed down to the ground towards the light. The Power of Movement in Plants A filament, 1.7 inch in length, was affixed nearly upright beneath the knee to the basal and vertical portion of a cotyledon; and its movements were traced during 14 h. in the usual manner. The Power of Movement in Plants Similar observations were made on 12 younger cotyledons with their upper halves enclosed within glass-tubes coated with black varnish, and with their lower halves fully exposed to bright sunshine. The Power of Movement in Plants On the side of the light the cotyledons were in close contact with the sand, which was a very little heaped up. The Power of Movement in Plants Though the sheath-like cotyledons of Phalaris are so extremely sensitive to apogeotropism, the first true leaves which protrude from them exhibited only a trace of this action. The Power of Movement in Plants Cassia tora.—The cotyledons of this plant are extremely sensitive to light, whilst the hypocotyls are much less sensitive than those of most other seedlings, as we had often observed with surprise. The Power of Movement in Plants The movement of the upper part above the knee of the same cotyledon, which projected at about an angle of 45o above the horizon, was observed at the same time. The Power of Movement in Plants The pots were now quickly laid horizontally, so that the upper parts of the cotyledons and of the hypocotyls of 9 seedlings projected vertically upwards, as proved by a plumb-line. The Power of Movement in Plants Nevertheless, any injury thus caused could be detected by removing the caps, and trying whether the cotyledons were then sensitive to light. The Power of Movement in Plants But tubes were used which fitted the cotyledons almost closely, and black paper was placed on the soil round each, to check the upward reflection of light from the soil. The Power of Movement in Plants Nineteen other cotyledons were, at the same time, similarly enclosed in tubes thickly painted with Indian ink. The Power of Movement in Plants The upper part of the cotyledon changed its course by at least as much as a rectangle six times on each of the two days. The Power of Movement in Plants As the glass-tubes, when unpainted, did not prevent the cotyledons from becoming greatly bowed, it cannot be supposed that the caps of very thin tin-foil did so, except through the exclusion of the light. The Power of Movement in Plants In a first trial, cotyledons which had grown to a moderate height were exposed for 8 h. before a paraffin lamp, and they became greatly bowed. The Power of Movement in Plants Caps only .2 or .22 inch in depth were placed over 4 other cotyledons, and now only one remained upright, one was slightly, and two considerably bowed to the light. The Power of Movement in Plants Weight can hardly be influential in the case of cotyledons, except in a few cases presently to be mentioned, but must be so with large and thick leaves. The Power of Movement in Plants Cyclamen Persicum: seedling, figure enlarged: c, blade of cotyledon, not yet expanded, with arched petiole beginning to straighten itself; h, hypocotyl developed into a corm; r, secondary radicles. The Power of Movement in Plants This was often evident when the movements of cotyledons standing in front of a window were traced. The Power of Movement in Plants As a control experiment, similar unvarnished and transparent tubes were tried, and they did not prevent the cotyledons bending towards the light. The Power of Movement in Plants In order to avoid prejudice, we asked three persons, who knew nothing about the experiment, to arrange the pots in order according to the degree of curvature of the cotyledons. The Power of Movement in Plants The cotyledons of some species of Trifolium are provided with a pulvinus, and others are destitute of one, and so it is with the leaves in the genus Sida. The Power of Movement in Plants These cotyledons, at 7 A.M. on the following morning, were again well expanded. The Power of Movement in Plants A young cotyledon or leaf after bursting free is brought down into its proper position, as already remarked, by epinasty, which, according to De Vries, long continues to act on the midribs and petioles. The Power of Movement in Plants But the sheath-like cotyledons of some Gramineae, for instance, those of Phalaris, are not green and contain very little starch; from which fact we may infer that they decompose little or no carbonic acid. The Power of Movement in Plants These cotyledons soon became plainly bowed towards the blackened side, evidently owing to the grease on this side having checked their growth, whilst growth continued on the opposite side. The Power of Movement in Plants Phalaris Canariensis: cotyledons after exposure in a box open on one side in front of a south-west window during 8 h. The Power of Movement in Plants As it was, the cotyledon moved up and down in the course of 16 h. The Power of Movement in Plants When the cotyledons were exposed before a bright lamp, standing on the same level with them, the upper part, which was at first Fig. The Power of Movement in Plants Seven cotyledons had their tips cut off for lengths varying between .1 and .16 of an inch, and these, when left exposed all day to a lateral light, remained upright. The Power of Movement in Plants Is it not possible, or even probable, that leaves and cotyledons, which have moved upwards in the evening through the action of apogeotropism during countless generations, may inherit a tendency to this movement? The Power of Movement in Plants These cleared stripes were not directed towards the window, but obliquely to one side of the room, so that only a very little light could act on the upper halves of the cotyledons. The Power of Movement in Plants The blades of all these cotyledons had attained almost their full size, viz. from 1 to 1 ½ inches in length, measured along their midribs. The Power of Movement in Plants These were placed at different times on the summits of 24 cotyledons, and they extended down for a length of between .15 and .2 of an inch. The Power of Movement in Plants Our next trial was made with short lengths of thin and fairly transparent quills; for glass-tubes of sufficient diameter to go over the cotyledons would have been too heavy. The Power of Movement in Plants Of these 8 cotyledons, five remained upright during 8 hours of exposure, although their lower parts were fully exposed to the light all the time; two were very slightly, and one considerably, bowed towards it. The Power of Movement in Plants The cotyledons of this plant, after the first leaf has begun to protrude, are but slightly apogeotropic, though they still continue to circumnutate. The Power of Movement in Plants The movements of the cotyledons were also traced both on vertical and horizontal glasses; their angles with the horizon were likewise measured at various hours. The Power of Movement in Plants But these cotyledons, after being extended horizontally, bowed themselves upwards as effectually as the unmutilated specimens in the same pots, showing that sensitiveness to gravitation is not confined to their tips. The Power of Movement in Plants The cotyledons can now assume the function of leaves, and decompose carbonic acid; they also yield up to other parts of the plant the nutriment which they often contain. The Power of Movement in Plants These cotyledons, therefore, were affected by a difference in the amount of light on their two sides, which the eye could not distinguish. The Power of Movement in Plants In the next trial much younger cotyledons were similarly treated, but were exposed to a rather obscure lateral light. The Power of Movement in Plants By this latter period the cotyledons had been dragged from beneath the pressed-down earth, but the upper part of the hypocotyl still formed nearly a right angle with the lower part. The Power of Movement in Plants In some species, the leaves sleep and not the cotyledons; in others, the cotyledons and not the leaves; or both may sleep, and yet assume widely different positions at night. The Power of Movement in Plants In other cases, leaves and cotyledons describe several vertical ellipses during the 24 h.; and in the evening one of them is increased greatly in amplitude until the blade stands vertically either upwards or downwards. The Power of Movement in Plants From the fact of leaves and cotyledons frequently rising a little in the evening, it appears as if diaheliotropism had to conquer during the middle of the day a widely prevalent tendency to apogeotropism. The Power of Movement in Plants In the Gramineae the summit of the straight, sheath-like cotyledon is developed into a hard sharp crest, which evidently serves for breaking through the earth. The Power of Movement in Plants The upward movement of the cotyledon during the afternoon and early part of the night is here plainly shown. The Power of Movement in Plants Ultimately not a trace of the former curvature is left, except in the case of the leaf-like cotyledons of the onion. The Power of Movement in Plants In this state the upper part of the hypocotyl and the cotyledons continue for some time to circumnutate, generally to a wide extent relatively to the size of the parts, and at a rapid rate. The Power of Movement in Plants The cotyledons of Phalaris bend much more slowly towards a very obscure light than towards a bright one. The Power of Movement in Plants In all these cases, the movement towards the light was extremely unequal in rate, and the cotyledons often remained almost stationary for some minutes, and two of them retrograded a little. The Power of Movement in Plants On the next day, by which time the dependent cotyledons had been dragged above the surface of the soil, the tied arch changed its course greatly nine times in the course of 14 ½ h. The Power of Movement in Plants The cotyledons at the two ends and in the central part of the box, would therefore have to bend in widely different directions in order to point to the light. The Power of Movement in Plants Lastly, the summits of 8 cotyledons were coated with flexible and highly transparent gold-beaters' skin, and all became as much bowed to the light as the free seedlings. The Power of Movement in Plants Leaves and cotyledons assume their nocturnal position by two means, by the aid of pulvini and without such aid. The Power of Movement in Plants The position which leaves and cotyledons occupy during the day, namely, more or less transversely to the direction of the light, is due, according to Frank, to what we call diaheliotropism. The Power of Movement in Plants The movements of the cotyledons are interesting from their complexity and rapidity, and in some other respects. The Power of Movement in Plants These are afterwards cast off merely by the swelling of the cotyledons. The Power of Movement in Plants From unknown causes, nutriment is sometimes stored in the hypocotyl or in the radicle, and then one of the cotyledons or both become rudimentary, of which several instances have been given. The Power of Movement in Plants Our imaginary seedling is now mature as a seedling, for its hypocotyl is straight and its cotyledons are fully expanded. The Power of Movement in Plants Before the cotyledons are fully expanded and have diverged, the hypocotyl generally straightens itself by increased growth along the concave side, thus reversing the process which caused the arching. The Power of Movement in Plants We shall have to recur to the cotyledons of the cabbage in a future chapter, when we treat of their sleep-movements. The Power of Movement in Plants As the arch grows upwards the cotyledons are dragged out of the ground. The Power of Movement in Plants The seed-coats are either left behind buried, or are retained for a time still enclosing the cotyledons. The Power of Movement in Plants In the former case the movement continues as long as the leaf or cotyledon remains in full health; whilst in the latter case it continues only whilst the part is growing. The Power of Movement in Plants It must not, however, be supposed that such cotyledons are immovably fixed in a horizontal position. The Power of Movement in Plants On the night of the 30th the cotyledons of the four were only slightly raised. The Power of Movement in Plants We have seen that the cotyledons of some species and not of others rise up vertically at night. The Power of Movement in Plants We refer to the movements of leaves and cotyledons which when moderately illuminated are diaheliotropic; but which change their positions and present their edges to the light, when the sun shines brightly on them. The Power of Movement in Plants We have seen a similar difference in the nyctitropic movements of the cotyledons in the genus Oxalis. The Power of Movement in Plants It would, therefore, not be rash to assume that the growing leaves of all plants circumnutate, as we have seen reason to conclude is the case with cotyledons. The Power of Movement in Plants The position of the two cotyledons was roughly sketched at various hours with the same general result. The Power of Movement in Plants Afterwards the more remarkable cases will be described in detail, with respect to cotyledons in the present chapter, and to leaves in the next chapter. The Power of Movement in Plants When the movements of leaves or cotyledons, furnished with a pulvinus and destitute of one, are compared, they are seen to be closely similar, and are apparently effected for the same purpose. The Power of Movement in Plants The cotyledons of 6 seedlings of Mimosa pudica were fastened open on cork and were thus exposed for 1 h. The Power of Movement in Plants The second leaf above the cotyledons resembles in all respects the leaves on fully developed plants. The Power of Movement in Plants June 20th; and the cotyledon fell till 10.15 P.M. in a nearly straight line. The Power of Movement in Plants We have seen that the cotyledons, instead of sinking like the leaflets, rise up vertically at night. The Power of Movement in Plants The cotyledons do not sleep at night. the first leaf consists of a single orbicular leaflet, which twists at night so that the blade stands vertically. The Power of Movement in Plants Thus, on one seedling the seventh leaf above the cotyledons was the first which bore any lateral leaflets, and then only a single one. The Power of Movement in Plants The result was, that the cotyledons of five out of the nine seeds thus placed were raised above the ground still enclosed within their seed-coats. The Power of Movement in Plants The cotyledons moved 7 times, either upwards or downwards; and at about 4 P.M. the great nocturnal sinking movement commenced. The Power of Movement in Plants With Solanum lycopersicum the cotyledons, after falling in the forenoon, zigzagged from side to side between 12 and 4 P.M., and then commenced rising. The Power of Movement in Plants The nine cotyledons of a seedling Pinus pinaster plainly circumnutated; and the figures described approached more nearly to irregular circles than to irregular ovals or ellipses. The Power of Movement in Plants In a large majority of the cases which were carefully observed, the cotyledons sink a little downwards in the forenoon, and rise a little in the afternoon or evening. The Power of Movement in Plants Here is a more interesting case: seedlings of Cassia tora in two pots, which had stood for some time on the table in the room just described, had their cotyledons horizontal. The Power of Movement in Plants The apex of the cotyledon stood only 3 3/4 inches from the vertical glass. The Power of Movement in Plants Drops of water placed quietly on these cotyledons produced no effect, but an extremely fine stream of water, ejected from a syringe, caused them to move upwards. The Power of Movement in Plants When a pot of seedlings was rapidly hit with a stick and thus jarred, the cotyledons rose slightly. The Power of Movement in Plants Mimosa pudica and albida.—The blades of several cotyledons of both these plants were rubbed or slightly scratched with a needle during 1 m. or 2 m.; but they did not move in the least. The Power of Movement in Plants Some other cotyledons, as those of Githago segetum, are much affected by a feeble light, but do not move when scratched by a needle. The Power of Movement in Plants Immediately before this latter fall the same cotyledon had risen from a vertically downward to a vertically upward position in 1 h. The Power of Movement in Plants In the same genus Oxalis the cotyledons of certain species stand vertically up, and those of other species vertically down, at night. The Power of Movement in Plants Seven other seedlings with their cotyledons in their normal nocturnal position, viz., vertical and closed, were exposed at the same time, and of these only 2 were killed.* The Power of Movement in Plants Nevertheless, in most of the cases given in the following list, the cotyledons may be as certainly said to sleep as may the leaves of any plant. The Power of Movement in Plants If we lay on one side the Leguminosae, the cotyledons of which are particularly liable to sleep, 140 genera remain; and out of these, the cotyledons of at least one species in 19 genera slept. The Power of Movement in Plants The tracing was not much magnified, and as the lines were plainly zigzag, the cotyledons must have moved a little laterally, that is, they must have circumnutated. The Power of Movement in Plants We have already seen well-marked instances of this latter fact with cotyledons, and so it is with leaves, as has been observed by Pfeffer and by ourselves. The Power of Movement in Plants We now come to the descriptive part of our work, and will begin with cotyledons, passing on to leaves in the next chapter. The Power of Movement in Plants But when the same seedlings were older and had produced small true leaves, the almost orbicular cotyledons, now .55 inch in diameter, moved vertically downwards at night. The Power of Movement in Plants On June 23rd, the cotyledons of one of these seedlings were 1.1 inch in length, and by 10 P.M. they had fallen from a horizontal position to 62o beneath the horizon. The Power of Movement in Plants The movement of the same hypocotyl after it had become straight and vertical, but with the cotyledons only partially expanded, is shown in Fig. The Power of Movement in Plants In the Leguminosae all the cotyledons which sleep, as far as we have seen, are provided with pulvini. The Power of Movement in Plants Trifolium strictum: diurnal and nocturnal positions of the two cotyledons and of the first leaf. The Power of Movement in Plants Apium graveolens.—The cotyledons at noon were horizontal, and at 10 P.M. stood at an angle of 61o above the horizon. The Power of Movement in Plants Exactly the same phenomenon was observed in the case of cotyledons. The Power of Movement in Plants The tip of the cotyledon passed across 10 divisions of the micrometer, that is, 1/50 of an inch, in 6 m. The Power of Movement in Plants Nevertheless, the weight of the cotyledons is so far influential, that when on another night the pot was turned upside down, they were unable to rise and thus to assume their proper nocturnal position. The Power of Movement in Plants On the following morning they were again flat and horizontal. the cotyledons of many other seedlings were at the same time not in any way affected. The Power of Movement in Plants Oxalis.—We now come to cotyledons provided with a pulvinus, all of which are remarkable from the continuance of the nocturnal movements during several days or even weeks, and apparently after growth has ceased. The Power of Movement in Plants We have met with only two brief notices of cotyledons sleeping. The Power of Movement in Plants We endeavoured to observe the circumnutation of the cotyledons, but as they close together unless kept exposed to a moderately bright light, and as the hypocotyl is extremely heliotropic, the necessary arrangements were too troublesome. The Power of Movement in Plants Secondly, according to Ramey**, the cotyledons of Mimosa pudica and of Clianthus Dampieri rise up almost vertically at night and approach each other closely. The Power of Movement in Plants The cotyledons of several other cruciferous plants were observed, but they did not rise sufficiently during the night to be said to sleep. The Power of Movement in Plants By July 9th the cotyledons appeared very old and showed signs of withering; but they stood at noon almost horizontally, and at 10 P.M. hung down vertically. The Power of Movement in Plants Leguminosae.—It may be seen in our list that the cotyledons of several species in nine genera, widely distributed throughout the Family, sleep at night; and this probably is the case with many others. The Power of Movement in Plants The great nocturnal rise of the cotyledons usually commences about 4 or 5 P.M., and on the following morning they are expanded or stand horizontally at about 6.30 A.M. The Power of Movement in Plants In Cassia the cotyledons of the ten species in the list rise up vertically at night and come into close contact with one another. The Power of Movement in Plants With several seedlings, the cotyledons assume a highly inclined position at night during so short a period of their life, that a doubt naturally arises whether this can be of any service to the plant. The Power of Movement in Plants The names of the plants, the cotyledons of which stand at night at an angle of at least 60o with the horizon, are arranged in the appended list on the same system as previously followed. The Power of Movement in Plants The cotyledons are very sensitive to light and will not expand if exposed to an extremely dim one. The Power of Movement in Plants Rate of Movement.—The movements of the hypocotyls and cotyledons of seedling cabbages of different ages have now been sufficiently illustrated. The Power of Movement in Plants The cotyledons of the other seedling were 1.3 inch in length, and a minute true leaf had been formed; they had fallen at 10 P.M. to 70o beneath the horizon. The Power of Movement in Plants Gossypium herbaceum.—It is remarkable that the cotyledons of this species behave differently from those of the last. The Power of Movement in Plants After the first two or three days the cotyledons diverge more during the day and cease to close at night. The Power of Movement in Plants On the next night the cotyledons occupied nearly the same position as before. The Power of Movement in Plants The cotyledons were still almost completely enclosed within the much-cracked seed-coats; and these were again covered up with damp adhesive soil pressed pretty firmly down. The Power of Movement in Plants Ipomoea bona-nox.—The cotyledons after a few days grow to an enormous size, those on a young seedling being 3 1/4 inches in breadth. The Power of Movement in Plants Those of O. Valdiviana and sensitiva, on the contrary, rise vertically up, so that their upper surfaces come into close contact; and after the young leaves are developed these are clasped by the cotyledons. The Power of Movement in Plants Trifolium strictum.—On the first day after germination the cotyledons, which are provided with a pulvinus, stood at noon horizontally, and at night rose to only about 45o above the horizon. The Power of Movement in Plants The cotyledons continued to act in nearly the same manner for 8 or 10 days from the period of germination; but the petioles had by this time become straight and had increased much in length. The Power of Movement in Plants This hypocotyl became almost straight, and the cotyledons were dragged from beneath the ground on the evening of the second day. The Power of Movement in Plants In only one instance was the right cotyledon twisted, with the true leaf twisted towards it; but this seedling was in an abnormal condition, as the left cotyledon did not rise up properly at night. The Power of Movement in Plants This whole case is remarkable, as with the cotyledons of no other plant have we seen any nocturnal movement except vertically upwards or downwards. The Power of Movement in Plants There are, however, some strong exceptions to this rule, as the cotyledons of Gossypium, Anoda and Ipomoea do not possess pulvini, yet continue to move and to grow for a long time. The Power of Movement in Plants But the cotyledons often emerge from the ground still tightly enclosed within the seed-coats, which apparently serve to protect them. The Power of Movement in Plants It moved in all directions; the lines from right and to left in the figure being parallel to the blades of the cotyledons. The Power of Movement in Plants On the 15th the first leaf was formed, and at night the cotyledons were vertical. The Power of Movement in Plants This holds good with species the cotyledons of which rise or sink so much at night that they may be said to sleep, as well as with others which rise only a little. The Power of Movement in Plants The cotyledons of Lotus Jacoboeus were not affected by 4 h. of complete darkness, but when placed under a double skylight and thus feebly illuminated, they quite lost their periodical movements on the third morning. The Power of Movement in Plants Both cotyledons of another and younger seedling were lightly rubbed in the same manner for 1 m., and after an interval of 32 m. each had risen 30o. The Power of Movement in Plants This seedling was so old that a very small true leaf had been developed, which at night was completely hidden by the closed cotyledons. The Power of Movement in Plants Citrus aurantium: two young seedlings: c, larger cotyledon; c', smaller cotyledon; h, thickened hypocotyl; r, radicle. The Power of Movement in Plants Again, certain species of Chaerophyllum and Corydalis produce only a single cotyledon;*** in the former the hypocotyl, and in the latter the radicle is enlarged, according to Irmisch, into a bulb. The Power of Movement in Plants In the several foregoing cases one of the cotyledons is delayed in its development, or reduced in size, or rendered rudimentary, or quite aborted; but in other cases both cotyledons are represented by mere rudiments. The Power of Movement in Plants On the other hand, there are many plants the cotyledons of which sleep, and are not in the least sensitive. The Power of Movement in Plants Nor did the cotyledons of any of the many other seedlings in the same pot rise; and so it was on the following night of June 5th. The Power of Movement in Plants Cassia mimosoides.—The cotyledons of this Indian species, 14 days after their first expansion, and when a leaf had been formed, stood during the day horizontal, and at night vertical. The Power of Movement in Plants At this period the upper part of the radicle is packed within the fruit parallel to the hypocotyl, and the single cotyledon is doubled back parallel to the latter. The Power of Movement in Plants Seedling cabbages circumnutate much more quickly, for the tip of a cotyledon crossed 1/100th of an inch on the micrometer in 3 m. The Power of Movement in Plants We have observed cases in only four genera, though we have vainly observed the cotyledons of many others. The Power of Movement in Plants Their hypocotyls were secured to sticks, and glass filaments bearing little triangles of paper were affixed to the cotyledons of both. The Power of Movement in Plants The cotyledons of S. Pfundii, an African water plant, are thick and fleshy; they are not sensitive and do not go to sleep. The Power of Movement in Plants The smaller cotyledon of one seedling was extremely thin, and not half the length of the larger one, so that it was clearly becoming rudimentary,* In all these seedlings the hypocotyl was enlarged or swollen. The Power of Movement in Plants The rate of growth, however, varies in all parts of the cotyledons, as may be observed in the measurements of the 8-days' old seedling. The Power of Movement in Plants The cotyledons of a seedling of Oxalis corniculata, which was feebly illuminated from above, moved downwards during the first morning in the normal manner, but on the second morning it moved upwards. The Power of Movement in Plants We thus see that the cotyledons became more widely open at noon on each succeeding day; and that they rose considerably each night, though not acquiring a vertical position, except during the first two nights. The Power of Movement in Plants On the other hand, the cotyledons of a few plants sink almost or quite vertically down at night; and in this latter case they clasp the upper part of the hypocotyl. The Power of Movement in Plants In all such cases the cotyledons may be said to sleep, for they act in the same manner as do the leaves of many sleeping plants. The Power of Movement in Plants Nevertheless, during this whole time and for ten days afterwards, these cotyledons rose vertically every night. The Power of Movement in Plants Pulvinated cotyledons, on the other hand, continue to rise at night for a much longer period, even for more than a month, as we shall now show. The Power of Movement in Plants It is considered by some great authorities to be a cotyledon, which term we will use without venturing to express any opinion on the subject.* The Power of Movement in Plants The cotyledons in another pot, similarly treated on another occasion, were open at 7 A.M. and remained open in the dark for 4 h. The Power of Movement in Plants Yet these same seedlings, when brought in the middle of the day from a moderately bright into only a moderately dull light raised, as we have seen, their cotyledons high above the horizon. The Power of Movement in Plants The cotyledons in all these cases became horizontal again in less than half an hour. The Power of Movement in Plants It thus appears that the cotyledons of Mimosa are less sensitive than those of the previously mentioned plants.* The Power of Movement in Plants A filament had been fixed to the midrib of one of the cotyledons, and the movement of the whole seedling was traced during two days. The Power of Movement in Plants On hitting a pot rapidly with a stick for 1 m., the cotyledons of two seedlings were considerably raised in the course of 11 m. The Power of Movement in Plants These observations were made before we were aware at what an extraordinarily rapid rate the cotyledons circumnutate, and are therefore liable to error. The Power of Movement in Plants Nevertheless it is extremely improbable that the cotyledons in the eight cases given, should all have been rising at the time when they were irritated. The Power of Movement in Plants Finally, there seems to exist some relation between * The sole notice which we have met with on the sensitiveness of cotyledons, relates to Mimosa; for Aug. The Power of Movement in Plants On Sept. 24th, between 8 A.M. and 5 P.M., the cotyledons moved five times up and five times down; they therefore described five irregular ellipses in the course of the 9 h. The Power of Movement in Plants Until this occurs light is excluded, and the cotyledons cannot decompose carbonic acid; but no one probably would have thought that the advantage thus gained by a little earlier cast- * 'Bull. The Power of Movement in Plants The cotyledons of several plants move up so much at night as to stand nearly or quite vertically; and in this latter case they come into close contact with one another. The Power of Movement in Plants Mimosa pudica.—The cotyledons were expanded for the first time on Nov. 2nd, and stood vertical at night. The Power of Movement in Plants On Dec. 15th, that is after 44 days, the cotyledons were still considerably raised at night; but those of another seedling, only one day older, were raised very little. The Power of Movement in Plants THE following chapter is devoted to the circumnutating movements of the radicles, hypocotyls, and cotyledons of seedling plants; and, when the cotyledons do not rise above the ground, to the movements of the epicotyl. The Power of Movement in Plants Mimosa albida.—A seedling was observed during only 12 days, by which time a leaf had been formed, and the cotyledons were then quite vertical at night. The Power of Movement in Plants This was ascertained by measuring the distance between the tips of the cotyledons of four seedlings at mid-day and at night. The Power of Movement in Plants It does not, however, follow from the above connection, that whenever a bulb is formed at an early age, one or both cotyledons will necessarily become superfluous, and consequently more or less rudimentary. The Power of Movement in Plants They were, however, cast off in the course of two or three days by the swelling of the cotyledons. The Power of Movement in Plants But in a future chapter we shall have to recur to the movements of certain cotyledons which sleep at night. The Power of Movement in Plants Yet according to M. Flahault, seedlings which have been prevented from casting their seed-coats whilst beneath the ground, are inferior to those which have emerged with their cotyledons naked and ready to act. The Power of Movement in Plants Oxalis corniculata: A and B the almost rudimentary pulvini of the cotyledons of two rather old seedlings, viewed as transparent objects. The Power of Movement in Plants Again, one species of Oxalis generally raised its cotyledons at night more than 20o and less than 60o above the horizon; so that this genus might have been included under two heads. The Power of Movement in Plants After an interval of two months, by which time the first and second true leaves had been developed, the cotyledons still performed the same movement. The Power of Movement in Plants Hypocotyl.—The hypocotyl protrudes through the seed-coats as a rectangular projection, which grows rapidly into an arch like the letter U turned upside down; the cotyledons being still enclosed within the seed. The Power of Movement in Plants The cotyledons of seedlings only a day old rise at night considerably, sometimes as much as afterwards; but there was much variation in this respect. The Power of Movement in Plants The cotyledons during the first 4 or 5 days of their life do not exhibit any plain nocturnal movement; but afterwards they stand vertically or almost vertically up at night. The Power of Movement in Plants All the individuals of the Solanum did not behave in the same manner, for the cotyledons of one circumnutated about the same spot between 2.30 and 10 P.M. The Power of Movement in Plants Seedlings of Githago segetum were feebly illuminated from above in the morning before their cotyledons had expanded, and they remained closed for the next 40 h. The Power of Movement in Plants The cotyledons are provided with a pulvinus, and its development will hereafter be described. The Power of Movement in Plants Other seedlings were placed in the dark after their cotyledons had opened in the morning and these did not begin to close until about 4 h. had elapsed. The Power of Movement in Plants The cotyledons of Oxalis rosea sank vertically downwards after being left for 1 h. The Power of Movement in Plants This movement facilitates the withdrawal of the tip of the epicotyl or of the cotyledons, as the case may be, from within the seed-coats and from the ground. The Power of Movement in Plants The cotyledons were still enclosed within the seed-coats; and the short hypocotyl, between the summit of the radicle and the cotyledons, was as yet only slightly arched. The Power of Movement in Plants On the following morning this cotyledon had fallen greatly from its vertical position by 8.15 A.M. The Power of Movement in Plants The cotyledons of another young seedling, exposed to the light, were fully open for the first time on a certain day, but were found completely closed at 7 A.M. on the following morning. The Power of Movement in Plants The figure described resembled pretty closely that above given; and this shows that the chief seat of movement is in the lower or basal part of the cotyledon. The Power of Movement in Plants With Cycas pectinata the cotyledons are hypogean, and a true leaf first breaks through the ground with its petiole forming an arch. The Power of Movement in Plants With Ranunculus ficaria two cotyledons are never produced, and here one of the secondary radicles is developed at an early age into a so-called bulb.** The Power of Movement in Plants It appears therefore that the cotyledons of this plant close and open at somewhat different periods from those of the foregoing species of the allied genera of Cucurbita and Lagenaria. The Power of Movement in Plants Thus with Cereus Landbeckii two little triangular projections, representing the cotyledons, are narrower than the hypocotyl, which is pear-shaped, with the point downwards. The Power of Movement in Plants Under these circumstances the cotyledons moved simply downwards from 7 A.M. till 2 P.M., after which hour and during a large part of the night they continued to rise. The Power of Movement in Plants Cotyledons.—On two occasions the movements of the cotyledons were traced on a vertical glass, and as the ascending and descending lines did not quite coincide, very narrow ellipses were formed; they therefore circumnutated. The Power of Movement in Plants In consequence of this injury it had emitted near the hypogean cotyledons two secondary shoots, and it was remarkable that both of these were arched, like the normal epicotyl in ordinary cases. The Power of Movement in Plants The cotyledons move only a little up and down: thus at 10.15 P.M. they stood only 10o higher than at noon. The Power of Movement in Plants In the case of Ipomoea leptophylla it is the petioles of the cotyledons which become arched whilst rising through the ground; and this occurred spontaneously when the seeds were fixed to the lids of jars. The Power of Movement in Plants But there were many exceptions to such simplicity of movement; thus the cotyledons of Ipomoea caerulea moved 13 times either upwards or downwards in the course of 16 h.. The Power of Movement in Plants The cotyledons of some individuals of Mimosa pudica and of Lotus Jacobaeus moved only once up and down in 24 h., whilst those of others performed within the same period an additional small oscillation. The Power of Movement in Plants This was conspicuous with those of Oxalis sensitiva, in which one cotyledon might be seen during the daytime rising up until it stood vertically, whilst the opposite one was sinking down. The Power of Movement in Plants The chief seat of movement therefore, at least when the cotyledons are rather old as in the present case, lies in the hypocotyl. The Power of Movement in Plants |
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