This deficiency seems to
result from the conditions to which the plants have been subjected, and partakes
of the nature of a monstrosity. All the flowers on the same plant are commonly
affected in the same manner. Such cases, though they have sometimes been ranked
as cleistogamic, do not come within our present scope: see Dr. Maxwell Masters
'Vegetable Teratology' 1869 page 403.) They are manifestly adapted for self-
fertilisation, which is effected at the cost of a wonderfully small expenditure
of pollen; whilst the perfect flowers produced by the same plant are capable of
cross-fertilisation. Certain aquatic species, when they flower beneath the
water, keep their corollas closed, apparently to protect their pollen; they
might therefore be called cleistogamic, but for reasons assigned in the proper
place are not included in the present sub-group. Several cleistogamic species,
as we shall hereafter see, bury their ovaries or young capsules in the ground;
but some few other plants behave in the same manner; and, as they do not bury
all their flowers, they might have formed a small separate subdivision.
Another interesting subdivision consists of certain plants, discovered by H.
Muller, some individuals of which bear conspicuous flowers adapted for cross-
fertilisation by the aid of insects, and others much smaller and less
conspicuous flowers, which have often been slightly modified so as to ensure
self-fertilisation.
Pages:
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30