It is therefore probable
that the pollen of the cleistogamic flowers has been modified in power, so as to
act on their own stigmas, for they yield an abundance of seeds. We may perhaps
account for the cleistogamic flowers consisting of the three forms, through the
principle of correlated growth, by which the cleistogamic flowers of the double
violet have been rendered double.
Vandellia nummularifolia.
Dr. Kuhn has collected all the notices with respect to cleistogamic flowers in
this genus, and has described from dried specimens those produced by an
Abyssinian species. (8/11. 'Botanische Zeitung' 1867 page 65.) Mr. Scott sent me
from Calcutta seeds of the above common Indian weed, from which many plants were
successively raised during several years. The cleistogamic flowers are very
small, being when fully mature under 1/20 of an inch (1.27 millimetres) in
length. The calyx does not open, and within it the delicate transparent corolla
remains closely folded over the ovarium. There are only two anthers instead of
the normal number of four, and their filaments adhere to the corolla. The cells
of the anthers diverge much at their lower ends and are only 5/700 of an inch
(.181 millimetres) in their longer diameter. They contain but few pollen-grains,
and these emit their tubes whilst still within the anther.
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