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Darwin, Charles, 1809-1882

"Effects of Cross and Self Fertilisation in the Vegetable Kingdom"

(10/59. See the interesting discussion on this whole subject by
O. Butschli in his 'Studien uber die ersten Entwickelungsvorgange der
Eizelle; etc. 1876 pages 207-219. Also Engelmann "Ueber Entwickelung von
Infusorien" 'Morphol. Jahrbuch' B. 1 page 573. Also Dr. A. Dodel "Die
Kraushaar-Algae" 'Pringsheims Jahrbuch f. Wiss. Bot.' B. 10.) We have
also seen that as plants became more highly developed and affixed to the
ground, they would be compelled to be anemophilous in order to
intercross. Therefore all plants which have not since been greatly
modified, would tend still to be both diclinous and anemophilous; and we
can thus understand the connection between these two states, although
they appear at first sight quite disconnected. If this view is correct,
plants must have been rendered hermaphrodites at a later though still
very early period, and entomophilous at a yet later period, namely,
after the development of winged insects. So that the relationship
between hermaphroditism and fertilisation by means of insects is
likewise to a certain extent intelligible.
Why the descendants of plants which were originally dioecious, and which
therefore profited by always intercrossing with another individual,
should have been converted into hermaphrodites, may perhaps be explained
by the risk which they ran, especially as long as they were
anemophilous, of not being always fertilised, and consequently of not
leaving offspring.


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