O. major: plant at first pale-yellow, soon becoming a dingy purplish-brown; stem simple, stout, erect, 1-2 feet high, with lanceolate scales; flowers closely sessile, forming a dense spike half the length of the stem, the corolla-tube nearly as broad as long, curved, with a very oblique limb, the upper lip entire or shortly two-lobed, the lower one three-lobed; upper part of the style and stamens usually covered with short glandular hairs, which are wanting in the lower parts. - Parasitical on the roots of the Broom, more rarely on those of the Furze. Fl. June, July.

Several other species are found, though less frequently, as O. clatior, a tall yellowish species, with the stamens hairy; O. rubra, red-brown; O. caryophyllacea, light or dark-brown; and O. minor, light yellowish-brown, the three latter being seldom over a foot high, with a short flower-spike.