Male Gametophyte of Cathaya
银杉的雄配子体

There are two prothallial cells in Cathaya, but their formation is different from that of the other genera of Pinaceae. A primary prothallial cell is cut off first and the division of this cell gives rise to 2 prothallial cells which remain intact in mature pollen grains. 3-celled pollen grains are formed. The interval between polination and fertilization is about 13 mon- ths. The two sperms are different in size.