P. Maheshwari classified the embryo sac on the basis of number of megaspore nuclei participating in embryo sac formation into following types:

(1) Monosporic embryo sac:

Only one megaspore nucleus forms embryo sac e.g., Polygonum, Oenothera.

(2) Bisporic embryo sac:

ADVERTISEMENTS:

Two megaspore nuclei take part in development of embryo sac e.g., Allium, Endymion.

(3) Tetrasporic embryo sac:

All the four megaspore nuclei take part in development of embryo sac e.g., Adoxa, Plumbago, Dursa, Fritillaria, Penaea, Plumbagella, Peperomia.