Prev | Current Page 400 | Next

Darwin, Charles, 1809-1882

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

)]
It is a curious fact that in all the foregoing polygamous, dioecious, and gyno-
dioecious plants in which any difference has been observed in the size of the
corolla in the two or three forms, it is rather larger in the females, which
have their stamens more or less or quite rudimentary, than in the hermaphrodites
or males. This holds good with Euonymus, Rhamnus catharticus, Ilex, Fragaria,
all or at least most of the before-named Labiatae, Scabiosa atro-purpurea, and
Echium vulgare. So it is, according to Von Mohl, with Cardamine amara, Geranium
sylvaticum, Myosotis, and Salvia. On the other hand, as Von Mohl remarks, when a
plant produces hermaphrodite flowers and others which are males owing to the
more or less complete abortion of the female organs, the corollas of the males
are not at all increased in size, or only exceptionally and in a slight degree,
as in Acer. (7/23. 'Botanische Zeitung' 1863 page 326.) It seems therefore
probable that the decreased size of the female corollas in the foregoing cases
is due to a tendency to abortion spreading from the stamens to the petals. We
see how intimately these organs are related in double flowers, in which the
stamens are readily converted into petals. Indeed some botanists believe that
petals do not consist of leaves directly metamorphosed, but of metamorphosed
stamens.


Pages:
388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412