SPERMATOPHYTES: GYMNOSPEKMS 



177 



danger of becoming confused and of forgetting that pollen 

 grains are asexual spores. 



98. Megasporophylls. The strobili composed of mega- 

 sporophylls become much larger than the others, forming 



-M 



FIG. 147. Finns sylvestris, showing mature cone partly sectioned, and showing car- 

 pels (sq, sq 1 , sq*) with seeds in their axils (g), in which the embryos (em) may be 

 distinguished; A, a young carpel with two megaspcrangia; B, an old carpel with 

 mature seeds (ch), the micropyle being below (M). After BESSEY. 



the well-known cones so characteristic of pines and their 

 allies (Figs. 145, a, b, c, 163). Each sporophyll is some- 

 what leaf -like, and at its base upon the upper side are two 

 megasporangia (Fig. 147). It is these sporangia which are 

 peculiar in each producing and retaining a solitary large 

 megaspore. This megaspore resembles a sac-like cavity in 



