(3) There is a endothelium,it initiated from the megasporocyte stage and enoughly development in the stage of uninucleate embryo sac.
（３）有珠被绒毡层，珠被绒毡层起始于大孢子母细胞时期，单核胚囊阶段高度发育，受精后从合点端逐渐退化。
