CHAPTER \T 



THE REPRODUCTIVE STRUCTURES: THE MALE 

 CONE AND :MALE GAMETOPHYTE 



The male reproductive structures are the male cones 

 with their microsporangia and male gametophytes. The 

 microsporangia produce microspores, which, upon ger- 

 mination, give rise to male gametophytes, and these 

 produce the sperms. 



THE MALE CONE 



The male cones, also called staminate cones or 

 staminate strobili, are much smaller than the female 

 and are usually comparatively slender, but the number 

 of sporophylls is larger (Fig. 46). In a few cases, like 

 EncepJialartos villosus, the two cones are not very differ- 

 ent in size or external appearance. In some species 

 the female cones reach a weight of ninety pounds, while 

 weights of seventy, fifty, and thirty pounds are not rare, 

 but any male cone weighing ten pounds must be regarded 

 as very large. 



Just before the microspores (pollen grains) are to be 

 shed, the axis of the cone elongates considerably, thus 

 separating the sporophylls and facilitating the dispersal 

 of spores. In this elongated condition the cone of 

 Cycas circinalis may reach a length of more than two 

 feet; while at the other extreme the cones of some species 

 of Zamia may not measure more than one or two inches 

 at this stage. 



100 



