TWYBLADE; a genus of the diandria order, belonging to the gynandra clas of plants. The species are numerous; but the most remarkable are the following.

1. The ovata, oval-leaved ophrys, or common twyblade, hath a bulbous, fibrated root; crowned by two oval, broad, obtuse, veined, opposite leaves; an erect, succulent, green stalk, six or eight inches high, naked above, and terminated by a loose spike of greenish flowers, having the lip of the nectarium bifid. The flowers of this species resemble the figure of gnats.

2. The spiralis, spiral orchis, or triple ladies-tresses, hath bulbous, oblong, aggregated roots; crowned by a cluster of oval, pointed, ribbed leaves; erect simple stalks, half a foot high; terminated by long spikes of white odoriferous flowers, hanging to one side, having the lip of the nectarium entire, and crenated.

3. The nidus-avis, or bird's-neck, hath a bulbous, fibrated, clustered root; upright, thick, succulent stalks, a foot high, sheathed by the leaves, and terminated by loose spikes of pale-brown flowers; having the lip of the nectarium bifid.

4. The anthropophora, man-shaped ophrys, or man-orchis, hath a roundish bulbous root, crowned with three or four oblong leaves; upright thick stalks, rising a foot and a half high; adorned with narrow leaves, and terminated by loose spikes of greenish flowers, representing the figure of a naked man; the lip of the nectarium linear triplicate, with the middle segment longest and bifid. There is a variety with brownish flowers tinged with green.

5. The infecifera, or insect-orchis, hath two roundish bulbous roots, crowned with oblong leaves; erect leafy stalks, from six to ten or twelve inches high, terminated by spikes of insect-shaped greenish flowers, having the lip of the nectarium almost five-lobed. This wonderful species exhibit flowers in different varieties, that represent singular figures of flies, bees, and other insects; and are of different colours in the varieties.

6. The monorchis, or musky ophrys, hath a roundish bulbous root; crowned with three or four oblong leaves; an erect naked stalk, six inches high; terminated by a loose spike of yellowish, musky-scented flowers.

All these six species of ophrys flower in summer, at different times in different parts, from May until July; and in most of the sorts exhibit a singularly curious appearance. The plants are all perennial in root, which are of the bulbous fleshy kind, from which the flower-stalks rise annually in spring, and decay in autumn; at which period is the proper time for removing the roots from one place to another. They all grow wild in Britain, &c.; are residents of woods, bogs, marshy grounds, sterile pastures, chalky soils, and the like places, where they flourish and display their singular flowers in great abundance, from which places they are introduced into gardens for variety; and having procured some plants at the proper season, and planted them in soils and situations somewhat similar to that where they naturally grow, the roots will abide for several years, and flower annually.

As to their propagation, it may be tried by seed in a shady border, as soon as it is ripe; likewise by offsets from the root, though they multiply sparingly in gardens: however, roots of some standing may be examined at the proper season, and any offsets separated and planted in the proper places.

OPHTHALMOSCOPY, a branch of physiognomy, which deduces the knowledge of a man's temper and manner from the appearance of his eyes.