[18]

Caladium apex rising apex falling [figure]

[18av]

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Chap. E 10

probable, but it may be asked, have other flowers been rendered inconspicuous so that they may not be frequently visited, or have they merely retained a former and primitive condition? If a plant were much reduced in size, so probably would be the flowers, through correlated growth, and this may possibly account for some cases; but the size and colour of the corolla are both extremely variable characters, and it can hardly be doubted that if large and brightly-coloured flowers were advantageous to any species, these could have been acquired through natural selection within a moderate lapse of time. in the course of ages. Papilionaceous flowers are manifestly constructed in relation to the visits of insects, and it seems improbable, from the general usual character of the group, that the progenitors

[18bv]

58 669

Chap. E 10

for cross-fertilisation.

Hawlett

Notwithstanding the several considerations just advanced, it seems to me highly improbable that plants bearing small and inconspicuous flowers should be or have been or should continue to be subjected to self-fertilisation for a long series of generations. I think so not from the evil which manifestly follows from self-fertilisation, in many cases even in the first generation, as with Viola tricolor, Sarothamnus, Nemophila, Cl Cyclamen, &c; nor from the probability of the evil increasing after several generations, for on this latter head I have not sufficient evidence, owing to the manner in which my experiments were conducted. But if plants bearing small and inconspicuous flowers did not profit by being occasionally intercrossed, it we might have been safely expected that all their flowers would have been rendered in the course of time cleistogene, as they would thus have profited largely by having to produce only a small quantity of safely-protected pollen. In In coming to this conclusion, I have We should bear in