The first cone also appears on the summit of the stem,
like the terminal cone in the Equisetaceae and the Club-Mosses. Thus
in certain types of the vegetable, as well as the animal creation of
earlier times, there was a continuation of features, afterwards divided
and presented in separate groups. In the present times, no one of
these families of plants overlaps the others, but each has a distinct
individual character of its own.
At the close of the middle geological ages and the opening of the
Tertiary periods, the Monocotyledons become abundant, the first plants
with flower and inclosed seed, though with no true floral envelope: but
not until the two last epochs of the Tertiary age do we find in any
number the Dicotyledonous plants, in which flower and fruit rise to
their highest perfection. Thus there has been a procession of plants
from their earliest introduction to the present day, corresponding to
their botanical rank as they now exist, so that the series of gradation
in the Vegetable Kingdom, as well as the Animal Kingdom, is the same,
whether founded upon succession in time or upon comparative structural
rank.
Some attempt has been made to reproduce under an artistic form the
aspect of the world in the different geological ages, and to present in
single connected pictures the animal and vegetable world of each period.
Pages:
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253