srEKMATOPIlVTE.S : (iYMNOSPElLMS 



m 



danger of becoming confused and of forgetting that pollen 

 grains are asexual spores. 



98. Megasporophylls.— The strobili composed of mcga- 

 sporophylls become much larger than the others, forming 



,j' 



f\ J 



Fig. 147. Pimis sylvestris, showing mature cone i)artly sectioned, and showing car- 

 pels {sq, sq^, sq^) with seeds in their axils (g), in which the enibr3'os (e?n) may be 

 distinguished; A, a young carpel with two megasjx.rangia; J], an old carpel with 

 mature seeds (ch), the micropyle being below (3/").— After Bessey. 



the well-known cones so characteristic of pines and their 

 allies (Figs. 145, a, b, c, 1G3). 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 



