) We thus see that cleistogamic flowers produce
seeds with a wonderfully small expenditure of pollen; and they produce as a
general rule quite as many seeds as the perfect flowers.
That the production of a large number of seeds is necessary or beneficial to
many plants needs no evidence. So of course is their preservation before they
are ready for germination; and it is one of the many remarkable peculiarities of
the plants which bear cleistogamic flowers, that an incomparably larger
proportion of them than of ordinary plants bury their young ovaries in the
ground;--an action which it may be presumed serves to protect them from being
devoured by birds or other enemies. But this advantage is accompanied by the
loss of the power of wide dissemination. No less than eight of the genera in the
list at the beginning of this chapter include species which act in this manner,
namely, several kinds of Viola, Oxalis, Vandellia, Linaria, Commelina, and at
least three genera of Leguminosae. The seeds also of Leersia, though not buried,
are concealed in the most perfect manner within the sheaths of the leaves.
Cleistogamic flowers possess great facilities for burying their young ovaries or
capsules, owing to their small size, pointed shape, closed condition and the
absence of a corolla; and we can thus understand how it is that so many of them
have acquired this curious habit.
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