A group of cells at the tip of the oogonium in certain green algae (Chlorophyta), such as the stonewort Chara and the mermaid's cup (Acetabularia).

2某些绿色藻类（绿藻门）中颈卵器顶部的一组细胞，例如轮藻属和伞藻属的冠细胞。