Why the colours came at all is a question closely connected with
the general story of the evolution of the flower, at which we
must glance. The essential characteristic of the flower, in the
botanist's judgment, is the central green organ which you
find--say, in a lily--standing out in the middle of the floral
structure, with a number of yellow-coated rods round it. The
yellow rods bear the male germinal elements (pollen); the central
pistil encloses the ovules, or female elements. "Angiosperm"
means "covered-seed plant," and its characteristic is this
protection of the ovules within a special chamber, to which the
pollen alone may penetrate. Round these essential organs are the
coloured petals of the corolla (the chief part of the flower to
the unscientific mind) and the sepals, often also coloured, of
the calyx.
There is no doubt that all these parts arose from modifications
of the leaves or stems of the primitive plant; though whether the
bright leaves of the corolla are directly derived from ordinary
leaves, or are enlarged and flattened stamens, has been disputed.
And to the question why these bright petals, whose colour and
variety of form lend such charm to the world of flowers, have
been developed at all, most botanists will give a prompt and very
interesting reply.
Pages:
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365