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Darwin, Charles, 1809-1882

"The Different Forms of Flowers on Plants of the Same Species"

This capsule contained an
abundance of plumose seeds, many of which appeared quite sound, but they did not
germinate when sown at Kew. Therefore the little bud-like flower which produced
this capsule probably was as destitute of pollen as were those which I examined.
Juncus bufonius and Hordeum.
All the species hitherto mentioned which produce cleistogamic flowers are
entomophilous; but four genera, Juncus, Hordeum, Cryptostachys, and Leersia are
anemophilous. Juncus bufonius is remarkable by bearing in parts of Russia only
cleistogamic flowers, which contain three instead of the six anthers found in
the perfect flowers. (8/22. See Dr. Ascherson's interesting paper in 'Botanische
Zeitung' 1871 page 551.) In the genus Hordeum it has been shown by Delpino that
the majority of the flowers are cleistogamic, some of the others expanding and
apparently allowing of cross-fertilisation. (8/23. 'Bollettini del Comizio
agrario Parmense.' Marzo e Aprile 1871. An abstract of this valuable paper is
given in 'Botanische Zeitung' 1871 page 537. See also Hildebrand on Hordeum in
'Monatsbericht d. K. Akad Berlin' October 1872 page 760.) I hear from Fritz
Muller that there is a grass in Southern Brazil, in which the sheath of the
uppermost leaf, half a metre in length, envelopes the whole panicle; and this
sheath never opens until the self-fertilised seeds are ripe.


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