622 Journal of Agricultural Research voi. xii, no. io 



PISTILS 



MoRPHOivOGY. — The carpels bearing a single orthotropous ovule are 

 arranged in a spiral on the fleshy cone-shaped receptacle. At maturity 

 they form dry achenes either set on the surface of the receptacle, as in 

 F. aynericana, or in shallow or deep pits, as in F. virginiana. The style 

 is inserted laterally on the inner side of the carpel and extends well above 

 the upper portion of the ovary. The pistil number is not constant on 

 the flowers of an inflorescence but is directly dependent upon the posi- 

 tion of the flower. 



Pistil sterility and dieciousness. — As has been previously men- 

 tioned, F. virginiana is, in the wild, typically diecious, the stamens having 

 been reduced to staminodia in the pistillate plants and the pistils, although 

 present and apparently normal, as far as can be seen superficially, in the 

 staminate flowers are nearly always functionless. This condition of 

 dieciousness has apparently remained unrecognized by systematists of 

 Fragaria. Apparently dieciousness is not confined to F. virginiana alone, 

 but is typical of most of the American species, except F. americana, 

 which is hermaphroditic, as is also the European species F. vesca. 



As early as 1760 dieciousness was recognized in F. elatior by Duchesne 

 {see Fletcher, j(5), who showed that the apparent sterility of the Hautboy 

 was in reality due to the weeding out of the unproductive male plants. 

 He also recognized partial separation of F. chiloensis into male and 

 female plants. A study of herbarium material of some of the American 

 species of Fragaria indicates that F. chiloensis from Alaska to Bolivia, 

 F. cuneijolia on Vancouver Island and in Washington and F. platypetala 

 from the north moraine of Sir Sandford Glacier are all diecious, at least 

 some plants produced pistillate flowers bearing staminodia, while others 

 bore flowers with well-developed stamens and apparently normal pistils 

 which showed no signs of setting fruit. On two plants of F. chiloensis 

 from Lake Merced, California, the primary flowers of staminate inflores- 

 cences were found to have set fruit, while the remaining flowers, although 

 well beyond the fruiting stage, showed no signs of setting. Supposedly 

 hermaphroditic plants of F. chiloensis from Alaska, grown at University 

 Farm for a number of years, produced few, if any, fruits, although they 

 blossomed profusely. 



Georgeson (19, p. ij), in speaking of F. chiloensis, which he used in his 



hybridization experiments, says : 



There is a decided variation among the plants; some are much more productive 

 than others, and some appear to bear only staminate flowers, though, as a rule, the 

 flowers are perfect. 



and again (20, p. 11) : 



The flowers are large and white and many of them staminate and sterile. 



The first plants of F. chiloensis brought to Europe by Frezier were all 

 pistillate and had probably been selected by him because of their fruiting 

 propensities. 



