280 DICECIOUS AND . Chap. VIL 



This, however, would be effected only under the con- 

 tingency of a reduced number of seeds, produced by 

 the females alone, being sufficient to keep up the 

 stock. 



There is another way of looking at the subject which 

 partially removes a difficulty that appears at first sight 

 insuperable, namely, that during the conversion of an 

 hermaphrodite into a dioecious plant, the male organs 

 must abort in some individuals and the female organs 

 in others. Yet as all are exposed to the same con- 

 ditions, it might have been expected that those which 

 varied would tend to vary in the same manner. As 

 a general rule, only a few individuals of a species 

 vary simultaneously in the same manner; and there 

 is no improbability in the assumption that some 

 few individuals might produce larger seeds than the 

 average, better stocked with nourishment. If the pro- 

 duction of such seeds were highly beneficial to a species, 

 and on this head there can be little doubt,* the 

 variety with the large seeds would tend to increase. 

 But in accordance with the law of compensation we 

 might expect that the individuals which produced such 

 seeds would, if living under severe conditions, tend 

 to produce less and less pollen, so that their anthers 

 would be reduced in size and might ultimately become 

 rudimentary. This view occurred to me owing to 

 a statement by Sir J. E. Smith f that there are female 

 and hermaphrodite plants of Serratula tinctoria, and 

 that the seeds of the former are larger than those of the 

 hermaphrodite form. It may also be worth while to 

 recall the case of the mid-styled form of Lythrum sali- 

 caria, which produces a larger number of seeds than the 



* See the facts given in 'The f* Trans. Linn. Soc.,' vol. xiii. 

 Effects of Cross and Self-fertilisa- p. 600. 

 tion,' p. 353. 



