Top-shaped multiciliate male gametes and the mature seed which bears only one embryo with two cotyledons, are characterised features of

Cycas is an evergreen palm like plant. The plant body is sporophytic differentiated into root, stem and leaves, sexual reproduction is of oogamous type takes place by the fusion of distinct male and female gametes. The male and female gametes are formed by the germination of microspores and megaspores which are borne on microsporophylls and megasporophylls. These microspores germinate to form male gametophyte that produces male gametes. The male gametes of Cycas are largest $(300\mu )$ in nature, visible to naked eye, oval in form and top shaped. It is spirally coiled in the anterior half with thousands of small cilia. After fertilization the ovule is connected into a seed. In the endosperm of seed lies a well developed embryo having two cotyledons, a plumule and a radicle.