Nor does the calyx differ, but the corolla
sometimes differs slightly in shape, owing to the different position of the
anthers. In Borreria the hairs within the tube of the corolla are differently
situated in the long-styled and short-styled forms. In Pulmonaria there is a
slight difference in the size of the corolla, and in Pontederia in its colour.
In the reproductive organs the differences are much greater and more important.
In the one form the stamens may be all of the same length, and in the other
graduated in length, or alternately longer and shorter. The filaments may differ
in colour and thickness, and are sometimes nearly thrice as long in the one form
as in the other. They adhere also for very different proportional lengths to the
corolla. The anthers sometimes differ much in size in the two forms. Owing to
the rotation of the filaments, the anthers, when mature, dehisce towards the
circumference of the flower in one form of Faramea, and towards the centre in
the other form. The pollen-grains sometimes differ conspicuously in colour, and
often to an extraordinary degree in diameter. They differ also somewhat in
shape, and apparently in their contents, as they are unequally opaque. In the
short-styled form of Faramea the pollen-grains are covered with sharp points, so
as to cohere readily together or to an insect; whilst the smaller grains of the
long-styled form are quite smooth.
Pages:
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338