

172 



STERILITY. 



aceous. This 



fact is well 



Chap. XVIII. 



n by the male flowers of 

 dioecious plants, which, according to Gallesio, 115 first becom 

 doable. Again, Gartner 116 often insists that the flowers of eve 

 utterly sterile hybrids, which do not produce any seed, generally 

 yield perfect capsules or fruit, — a fact which has likewise been 



e 



peatedly observed by Naudin with the Cucurbitac 

 the production of fruit by plants rendered sterile through any 

 other and distinct cause is intelligible. Kolreuter has also ex- 

 pressed his unbounded astonishment at the size and development 

 of the tubers in certain hybrids ; and all experimentalists m have 

 remarked on the strong tendency in hybrids to increase by roots, 

 runners, and suckers. Seeing that hybrid plants, which from 

 their nature are more or less sterile, thus tend to produce double 

 flowers; that they have the par 

 the fruit, perfectly developed, e^ 

 that they sometimes yield giga 



including the seed, that is 



when containing no seed; 



c roots; that they almost 



iably tend to increase largely by suckers and 



means 



d knowing, from the many facts 



riven in 



the earlier parts of this chapter, that almost all organic beings 

 when exposed to unnatural conditions tend to become more or 



lost probable view that with 



less sterile, it seems much the most 



cultivated plants sterility is the exciting cause, and double 

 flowers, rich seedless fruit, and in some cases largely-developed 



, are the indirect results — these results 



organs of vegetation, &c, are the indirect results- 

 having been in most cases largely increased through continued 

 selection by man. 



' 



b 



us i Teoria delta Riproduzione Veg.,' 1816, p. 73. 



116 ' Bastarderzeugung,' s. 573. 



»7 Ibid., s. 527. 



