ORDER CLXXXII.—JUNCAGINEÆ.—THE ARROWGRASS TRIBE.
Insignificant bog plants, with grassy leaves, and central spikes or racemes of greenish yellow flowers.
ORDER CLXXXIII.—ORCHIDACEÆ.
The plants belonging to this order may be divided into two kinds, those that grow in the earth, and those which require to have their roots suspended in the air; the latter being the beautiful tropical plants called Orchideous Epiphytes. Most of the terrestrial Orchidaceæ are British plants belonging to several genera, the most curious of which are Orchis, Habenaria, Ophrys, Aceras, Nœttia, Epipactis, and Malaxis. Nearly all the British Orchidaceæ have tuberous roots, which remain above ground, a new tuber being formed every year. The leaves are alternate, with an entire margin, without any footstalk, and sheathing the stem at the base. The flowers are produced in a spike, furnished with bracts, and though they are very irregular in their forms, there are cer tain particulars in which they all agree. Though in reality sessile, they appear to have each a footstalk, but this footstalk is only the long twisted ovary (c in fig. 146), which is one-celled
Fig. 146.—Orchis Morio. and many-seeded, and which serves to support the calyx and corolla of the flower, which are both above it. The calyx consists of three sepals, one of which has the appearance of a hood (a), and the others (b b) look like wings. The petals are very disproportionate in their size; two are generally very small, and are only seen peeping beneath the hood of the calyx; while the third (d), which is called the labellum, or lip, is very large, and hangs down. In the centre of the flower is a singular mass, called the column, composed of the stamens and pistil, grown together (see a in fig. 147). In this column there is one perfect
Fig. 147.—Pollen Masses of the Orchis. anther (b), and two imperfect ones (c c). The perfect anther consists of a pouch or bag, which, when opened, displays two stalked masses of globular pollen, one of which (d) is pulled down to show its appearance, while the other remains in its case at (e). The stigma is a sort of cup half full of a glutinous fluid, but it appears entirely shut out from the pollen, which is not only enclosed in its pouch or bag, but is of such a solid waxy nature as to prevent any possibility of its being carried by wind or insects to the stigma. Nature, however, has contrived a means of obviating the difficulty. At the foot of each stalk of the pollen masses, there is a little protuberance, covering a gland, through which the pollen descends to the stigma, and thence to the ovary or germen.
The different genera are distinguished, partly by the manner in which the granules of the pollen adhere together, and partly by the shape of the flowers; and their different species vary principally in the form of the labellum. In the genera Orchis and Habenaria, the labellum is drawn out behind into a kind of spur (see e in fig. 146); and in others it assumes strange shapes, as in the Man Orchis (Aceras anthropophora), where the labellum looks like a little man; and in the Lizard Orchis (A. or Orchis hircina) where the labellum is drawn out into a long tail, which looks like the tail and long body of the lizard, while the petals, which are long and narrow and bent back, look like the hind legs. In the genus Ophrys, the labellum also takes strange shapes, sometimes resembling a bee, at others a fly, and at others a spider. In the genus Cypripedium, the two side stamens bear anthers and pollen, and only the central one is imperfect.