SPERMATOPHYTA 



355 



both kinds of strobili are compound, the sporophylls arising on secondary 

 axes borne in the axils of bracts. 



Staminate Strobilus. The staminate strobilus consists of an axis bear- 

 ing a series of bracts arranged in opposite pairs. These are connate in 



Fig. 302. A, Ephedra viridis, showing portion of staminate plant with strobili, two-fifths 

 natural size; B and C, Ephedra antisiphilitica, showing a staminate {B) and an ovulate (C) 

 strobilus, enlarged. {B and C, after Watson.) 



Gnetum and imbricate in the two other genera. In the axil of each bract, 

 except the lower ones, is a "staminate flower," representing a simple 

 strobilus. This consists, in Ephedra and Gnetum, of a stalk bearing two 

 (or, in Ephedra, up to six or eight) terminal microsporangia and a pair of 

 basal scales (Figs. 302B and 304C). In Welwitschia the staminate flower 

 is composed of two opposite pairs of basal scales investing a whorl of six 



