Edwards's Bot Reg. (1821) sub t. 573
Sympodial terrestrial or epiphytic plants with or without distinct rhizomes. Stem very short or rarely elongated, or with fat pseudobulbs consisting of one internode. Leaves few to several, spirally arranged or in two rows, sheathing at the base, glabrous or sometimes pubescent, plicate, deciduous or persistent, convolute, thin-textured. Inflorescence a lateral or basal, few- to many-flowered raceme. Flowers small to rather large, resupinate, often showy. Sepals free. Petals free, often fairly similar to the dorsal sepal, but sometimes rather different in shape. Lip adnate to the column along the entire length of the latter, usually with a distinct spur, rarely spur absent. Column-foot absent. Pollinia 8, solid, caudicles present, stipe absent, viscidium present.
Central America (one species), tropical and southern Africa, Madagascar, throughout tropical Asia, China and Japan, Indonesia, the Philippines, Papua New Guinea, Pacific islands, east to Tahiti. About 100 species; in New Guinea c. 30 species.
Mainly terrestrial in rain forest; also epiphytic on tree trunks and major branches. Found both in the lowlands and in the mountains.
The often attractive flowers of this genus are almost always distinctly spurred. They are of a more delicate consistency than those of most orchids. Phaius and Cephalantheropsis (the latter not found in New Guinea) are related genera. As in those genera all parts of the plant (including the flowers) turn bluish when bruised. Some New Guinea species deviate considerably from the type of Calanthe commonly seen in cultivation, e.g. Calanthe caulescens, Calanthe rhodochila and Calanthe versteegii. The last mentioned is so unusual that it was even described as a member of the genus Giulianettia (now included in Glomera).
The following sections accommodate the New Guinea species of Calanthe:
Preptanthe - plants with large, exposed pseudobulbs and deciduous leaves, lip spurred;
Rhodochilus - plants with short or elongated stems, a simple or almost simple spurred lip with relatively small blade, with persistent floral bracts;
Calanthe - plants with very short stems, lip spurred, usually distinctly lobed, with persistent floral bracts;
Styloglossum - plants with very short stems, lip spurred, not or weakly lobed, with deciduous floral bracts;
Aceratochilus - plants with very short stems, lip not spurred, not or weakly lobed, with deciduous floral bracts.