SEXUALITY AND THE ENVIRONMENT. 239 



Mr. Darwin also records * how " a tendency to the 

 separation of the sexes in the cultivated Strawberry seems 

 to be much more strongly marked in the United States than 

 in Europe ; and this appears to be the result of the direct 

 action of climate on the reproductive organs." Quoting 

 from the Gardener's Chronicle, f he adds, " Mary of the 

 varieties in the United States consist of three forms, namely, 

 females, which produce a heavy crop of fruit, — of hermaphro- 

 dites, which ' seldom produce other than a very scanty crop 

 of inferior and imperfect berries,' — and of males which pro- 

 duce none. . . . The males bear large, the hermaphrodites 

 mid-sized, and the females small flowers. The latter plants 

 produce few runners, whilst the two other forms produce 

 many; ... we may therefore infer that much more vital 

 force is expended in the production of ovules and fruit than 

 in the production of pollen." 



Conversely, as runners were more abundant with male 

 and hermaphrodite plants, we see here an instance of vege- 

 tative growth correlated with the male elements at the expense 

 of the female. 



Sexuality and the Soil. — Miiller has given two instruc- 

 tive cases where it is pretty certain that the soil was a chief 

 cause of the separation of the sexes.J Dianthus deltoides, 

 near Lippstadt, offers interesting gradations from her- 

 maphroditism to gynodioecism and gynomonoecism. " On 

 the border of a meadow, of some hundred stems examined by 

 myself, all the flowers, without exception, proved to be pro- 

 tandrous, with a normal development of the anthers and 

 stigmas. On the grass-grown slope of a sandy hill likewise, 

 all the stems produced protandrous flowers, but on many 

 stems the stamens, although emerging above the petals 



♦ Varms of Flowers, p. 293. t 1861, p. 716. 



J Natiure, vol. xxiv., p. 532. 



