Male Gametophyte of Microcycas calocoma

Abstract
Pollination appears to take place during the last week in August and the first 2 weeks in September. The pollen is shed in the 3-celled condition. The generative cell divides into "stalk" cell and body cell, the latter undergoing 8-10 successive divisions, each time cutting off a body cell. Centro-somes are at no time present in the spermatogenous cell. The body cells divide once, producing 2 sperm mother cells. In 1 exceptional case, a daughter cell, which normally would have become a body cell, remained spermatog-enous. The pollen tube moves through the nucellar tissue by solution of cell walls and absorption of cell contents. The single prothallial cell remains small until cessation of activity of the spermatogenous cell, then grows rapidly into and through the stalk or sper-matogenous cell. The spermatogenous cell remains turgid during the passage of the prothallial cell. The blepharoplast appears in the young body cells as an aggregate of small granules. After the enlargement and vacuolation of the blepharoplast, pieces are broken off which scatter in the cytoplasm of the sperm mother cell. This may be a process of disintegration. The formation of the ciliated band could not be determined. The number of sperms is 16-20.