Botany for Ladies: or, A Popular Introduction to the Natural System of Plants, According to the Classification of De Candolle.Loudon, Mrs. (Jane)
Science
Botany for Ladies: or, A Popular Introduction to the Natural System of Plants, According to the Classification of De Candolle.
Loudon, Mrs. (Jane)
Botany; Plants -- Classification
The common Bedstraw (_Galium vernum_) is a British weed, common in
dry fields and on little knolls, which produces its cluster of bright
yellow flowers in July and August. The flowers are so small that it is
difficult to examine them in detail, but, by the aid of a microscope,
the ovary will be found to be inclosed in the tube of the calyx as in
the other Rubiaceæ, though the calyx has hardly any limb. The corolla
is what is called rotate or wheel-shaped, and its limb is divided into
four segments. There are four short stamens, with their filaments
inserted in the throat of the corolla, and two very short styles. The
fruit is a dry capsule inclosing two seeds. Thus far the construction
of the plant agrees with the other Rubiaceæ, but the stem is square,
and the leaves are different, for they are without footstalks, and are
disposed in what is called a whorl (see _fig._ 40). The whorl, however,
according to Professor De Candolle, does not consist entirely of
leaves; but of two opposite leaves and two or more stipules, which are
so like the leaves as scarcely to be distinguished from them, though
upon close examination, it will be found that the leaves have buds in
their axils (that is between them and the stem), which the stipules
have not. This theory is not adopted by Dr. Lindley, who considers the
whorl to consist entirely of leaves, and to be one of the distinctive
marks of his order Galiaceæ.
[Illustration: FIG. 40.—WHORL OF LEAVES OF BEDSTRAW. (_Galium vernum._)]
All the plants in this division of Rubiaceæ agree with the common
Bedstraw (_Galium vernum_) in the formation of their leaves and stem;
but the species of Galium are distinguished by the margins of the
leaves and the principal veins, in nearly all the species, being
covered with prickles, which in some cases point forwards, and in
others are bent back, so as to catch everything they touch. This is
particularly the case with the leaves of the plant called Goose-grass,
or Cleavers (_Galium aparine_); and its fruit is covered with hooked
bristles, which take so firm a hold as to make it difficult to separate
them from anything they have caught hold of. The pretty little weed
called Field Madder (_Sherardia arvensis_), the fragrant Woodruff,
(_Asperula odorata_), and _Rubia peregrina_, the only British species
of Madder, all agree with Galium in its more important characters;
and as they are all common weeds, my readers will probably find it
interesting to trace the differences between them. Galium and Rubia
agree in having scarcely any limb to the calyx, and a rotate corolla;
but the limb, which is only four-parted, or even three-parted, in
Galium, has always five lobes in Rubia; there are also five stamens in
Rubia, and the fruit is a berry; whereas there are only four stamens in
Galium, and the fruit is dry. Sherardia agrees with Asperula in having
a funnel-shaped corolla with a four-cleft limb; but in Sherardia the
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