These
cleistogamic flowers produced an abundance of seed. Later in the season perfect
flowers appeared. With plants in a state of nature the flowers open only in the
early morning, as I have been informed by Mr. Wallis, who particularly attended
to the time of their flowering. In the case of D. Anglica, the still folded
petals on some plants in my greenhouse opened just sufficiently to leave a
minute aperture; the anthers dehisced properly, but the pollen-grains adhered in
a mass to them, and thence emitted their tubes, which penetrated the stigmas.
These flowers, therefore, were in an intermediate condition, and could not be
called either perfect or cleistogamic.
A few miscellaneous observations may be added with respect to some other
species, as throwing light on our subject. Mr. Scott states that Eranthemum
ambiguum bears three kinds of flowers,--large, conspicuous, open ones, which are
quite sterile,--others of intermediate size, which are open and moderately
fertile--and lastly small closed or cleistogamic ones, which are perfectly
fertile. (8/16. 'Journal of Botany' London new series volume 1 1872 pages 161-
4.) Ruellia tuberosa, likewise one of the Acanthaceae, produces both open and
cleistogamic flowers; the latter yield from 18 to 24, whilst the former only
from 8 to 10 seeds; these two kinds of flowers are produced simultaneously,
whereas in several other members of the family the cleistogamic ones appear only
during the hot season.
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