SEXUALITY AND THE ENVIRONMENT. 247 



M. Arbanmont found tliat young seeds gave rise to plants of 

 extraordinary vegetative vigour ; moderately aged ones gave 

 rise to corresponding moderately vigorous plants with both, 

 male and female flowers ; while older seeds gave rise to still 

 less vigorous plants, but which, when properly nourished, 

 formed female buds.* M. F. Cazzuolaf also found that 

 melons raised from fresh seed bore a larger proportion of 

 male flowers than female ; while older seed bore more female 

 flowers : and this has been confirmed. 



Another interesting result was obtained by M. Triewald, 

 who grcAv twenty-one out of twenty-four melon seeds which 

 were forty-one years old. The branches were very narrow, 

 yet they produced early and plenty of good melons. [j: A 

 cause of the differences of vigour in the plants raised from 

 seeds of different age is, perhaps, connected with, the fact 

 that fresh melon seeds contain a neutral oil, which becomes 

 more and more acid by keeping. This increased acidity 

 coincides with a diminished germinative power ; § and 

 proportionately, therefore, less liable to run into excessive 

 vegetative growth. 



The next condition to be observed is that resulting from 

 sowing seeds of diclinous plants thickly or thinly. Hoff- 

 man's experiments || in this direction showed that 283 male 



* Bull, de la Soc. de Bot. de Fr., 1878, p. 111. 



t Bull, de Tuscan. Hort. Soc, 1877. 



+ Gard. Chron., 1879, p. 470. 



§ M. Ladureau in Ann. Agronomiques. Mr. Darwin also found that 

 fresh seeds of Iheris grew at first more vigorously than others {Cross 

 and Self-fertilisation, etc., p. 103). 



II Gard. Chron., 1879, p. 762 ; see also Bot. Zeit, xliii., 1885, p. 145, 

 seqq. ; also Jenaisch Zeitschr. f. Naturwiss, xix. (1885), sup. ii., pp. 108- 

 112. The following were the plants with which he experimented : 

 Lychnis diurna, L. vespertina, Valeriana dioica, Mercurialis annua, Buniex 

 Acetosella, Spinacia oleracea, and Cannahis sativa. 



