So it defined as crassinucellate.The megaspore mother cell divides transversally to form a linear megaspore tetrad.The megaspore at the chalazal end develops into the embryo sac mother cell.

• 大孢子母细胞经横向分裂后产生一直线形的大孢子四分体，之后位居合点端之大孢子发育成胚囊母细胞。