SPEKMATOPHYTES : GYMNOSPEPvMS 



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 



Fig. 147. Pinug sylrestris, showing mature cone partly sectioned, and showing car- 

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

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

 mature seeds (ch), the micropyle being below (Jf). — After Besset. 



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. 117). It is these sporangia which are 

 peculiar in each producing and retaining a solitary large 

 megaspore. This megaspore resembles a sac-like cavity in 



