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exprelTive name I could think of, being more proper than that
oflozuers ; as the parts which conllitutc the flowers of a fern
are much too minute for the infpeilion of the naked eye.
In plate i it, d, c, f, I have given a borrowed figure of a
fingle globe, or feparate feed-veficl. Thefe arc placed in
great numbers on the under fide of the lobes, and every af-
femblage of them covered with a thin tranfparent film, at firft
of a pale whitifh colour, and as it advances in growth of a
brownifhhue ; before the feeds are ripe it burfts open, and
difcovers the little globes, which are afterwards greatly cn-
creafed in magnitude, much extending laterally and enlarging
the fpace occupied by the aflemblage while wrapped up in
its primary cover. The globes, or feparate feed-vefiels, arc
of a figure truly fpherical, and are attached to the furface of
the leaf by a ihorf footftalk, g. They are furroundcd with
an articulate chain, or elaftic ring, e, d, which, when the
feeds are ripe, breaks at h, tears open the fhell i in a vertical
direflion, difcharges the feeds, and, as the chain further con-
trafts itfelf, throws open the two valves f, in an horizontal di-
reSion, by which the fpace of the aflemblage is again confi-
derably enlarged, and hence it is that fome of the polipodia,
and many of the afplenia, become covered with feed-vcflels in
the laft ftages of their growth, and thereby become acrofticha
according to the prefent mode of arrangement.
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