The ovule is bitegminous and tenuinucellate.The archesporial cell locates under the nucellus epidermis, which develops into fuctional megasporocyte.

原细位于珠心表皮之下，直接起大细的。

Tapetum (pl. tapeta) A food-rich layer surrounding the spore mother cells in the anthers of vascular plants.

管植物花粉囊内包围细的富含营养物质的一层结构。