GNETALES— WELWITSCHIA 



399 



more rapidly at the sides, producing the broad, thin wings. While 

 the wings are extremely thin, an abundance of wavy fibers makes 

 them rather tough. They doubtless function in seed dispersal. 



lb 



B 



Fig. 375. — WelwUschia mirahilis: development of ovulate flower: A, longitudinal 

 section of tip of ovulate cone: the lowest flower at the right shows the nucellus, with 

 inner integument (?) and {p) outer integument (perianth) ; the flower next above shows 

 the same structures in earlier condition; B, older ovulate flower, with the female game- 

 tophyte in an earlier free nuclear stage; b, bract; C, still later stage, with female game- 

 tophyte (g) in late free nuclear stage; A, X20; B and C, X50. 



At first the perianth, which Pearson prefers to regard as an outer 

 integument, much exceeds the inner integument, but, as the time 

 of polHnation approaches, the inner integument grows rapidly until 

 it protrudes beyond both the subtending bract and perianth (figs. 

 375 and 373). 



