88 PEINCIPLES OF PLANT-TEEATOLOGY. 



this was accompanied by degeneration of the inferior 

 ovary, the number of carpels becoming reduced (fig. 

 97). Female flowers of the hornbeam {Garpinus 

 Betuhiff), hetter developed than normally,each contained 

 a single stamen. Female flowers of the red campion 

 {Lychnia dioica) infested by the mycelium of Ustilago 

 violacea become hermaphrodite owing to the develop- 

 ment of the otherwise rudimentary stamens. 



Robbins found that the peloric ray-florets of Gail- 

 lavilia aristata, which in their normal zygoraorphic 

 condition are sterile (neviter), were furnished with 



Fig. 97. — Begonia. Female flower become hermaphrodite through 

 the appearance of stamens. (J. Weathers.) 



stamens and pistil, both perfectly developed. This is 

 one of the very numerous instances in which one 

 reversionary change is concomitant with another with 

 which it would seem to be closely correlated. 



The ray-florets of the Compositse represent diffe- 

 rentiations of the disk-florets in two main directions : 

 zygomorphism of the corolla and unisexuality or 

 sterility. 



Blaringhem obtained by artificial mutilation herma- 

 phrodite flowers in the maize; but the stamens were 

 never fertile, and they did not appear until a little 

 before maturity of the plant, long after the ovaries had 

 been fertilized. This is a good case of the late appear- 



