Between the sexless, female and
hermaphrodite states of these latter flowers, the finest gradations may be
traced, as Hildebrand has shown. (Introduction/10. 'Ueber die
Geschlechtsverhaltnisse bei den Compositen' 1869 pages 78-91.) He also shows
that there is a close relation between the size of the corolla in the ray-
florets and the degree of abortion in their reproductive organs. As we have good
reason to believe that these florets are highly serviceable to the plants which
possess them, more especially by rendering the flower-heads conspicuous to
insects, it is a natural inference that their corollas have been increased in
size for this special purpose; and that their development has subsequently led,
through the principle of compensation or balancement, to the more or less
complete reduction of the reproductive organs. But an opposite view may be
maintained, namely, that the reproductive organs first began to fail, as often
happens under cultivation, and, as a consequence, the corolla became, through
compensation, more highly developed. (Introduction/11. I have discussed this
subject in my 'Variation of Animals and Plants under Domestication' chapter 18
2nd edition volume 2 pages 152, 156.) This view, however, is not probable, for
when hermaphrodite plants become dioecious or gyno-dioecious--that is, are
converted into hermaphrodites and females--the corolla of the female seems to be
almost invariably reduced in size in consequence of the abortion of the male
organs.
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