Plants -- Identification; Wild flowers -- Great Britain
Fertilisation is brought about much in the same way in many of the
composite flowers:--The anthers open inwards, discharging their pollen
within the tube formed by themselves, and just above the stigma which,
as yet, is immature. The style then lengthens, pushing its way up
through the anther-tube, and brushing up the pollen by means of the
tufts of hairs on its surface. At this stage a dense cluster of pollen
cells, completely covering the top of the style, may be seen projecting
above the tube of the corolla, and the pollen is sooner or later
scattered, the distribution being aided greatly by the various insects
which visit the flowers. The upper part of the style now divides into
two parts, and the branches diverge, exposing the stigmatic surfaces
which form the inner sides of the fork. It will thus be seen that the
florets are not self-pollinated, since the stigma is generally mature
after the pollen has all been removed from the same flower.
Our first example of this order is the Yellow Goat's-beard (_Tragopogon
pratensis_), also known as Jack-go-to-bed-at-noon. This is a common
wayside plant, of a glaucous green colour, with a milky sap. Its stem is
erect, from one to two feet high, and the whole plant is smooth. The
flower-heads are solitary, large, yellow, and surrounded by a single row
of narrow bracts that are united below; and the peduncle is thickened at
the top. The bracts are generally as long as the florets, and the latter
usually close about the middle of the day. The fruit is long and narrow,
with longitudinal ridges; and the pappus consists of rows of feathery
hairs which interlock and form a very shallow cup. The flowers bloom
during June and July.
[Illustration: THE YELLOW GOAT'S-BEARD.]
The Bristly Ox-tongue (_Helminthia echioides_ or _Picris echioides_),
also a common plant, is more or less covered with rigid, hooked
bristles, each of which arises from a swollen, white base; and it has a
milky sap. The stem is stout, branched, very bristly, and grows from two
to three feet high. The leaves are simple and toothed, the upper ones
cordate and embracing the stem, and the lower ones _auricled_ or eared.
The heads are terminal, consisting of yellow, ligulate florets,
surrounded by five large cordate bracts. The fruit is brown, curved,
with transverse ridges and a stalked pappus of feathery hairs. This
species flowers from June to September. It is shown on Plate
III.
In the same genus we have the Hawkweed Picris (_P. hieracoides_) which
bears yellow flowers from June to September. Its stem, more slender than
that of the last species, is from two to three feet high, branched
towards the top, and rough with hooked bristles; and the leaves are
lanceolate and toothed. There are numerous heads of flowers, about an
inch in diameter, usually arranged in a corymb, but sometimes in an
umbel, and there are bracts on the peduncles.
[Illustration: THE HAWKWEED PICRIS.]
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