Dendrobium section Calcarifera J.J.Sm.,
Bull. Dép. Agric. Indes Néerl. 15 (1908) 14.
Rhizomes short. Stems much elongated and slender, usually fleshy (almost wiry in Dendrobium lancifolium), many-leaved, branching or not. Leaves glabrous, often short-lived and rather thin-textured. Inflorescences lateral from the upper part of the stem, racemose or 1-flowered. Flowers medium-sized, resupinate, long-lived, often showy, mentum large, spur-like, not parallel with the ovary but often at almost right angles to it. Lip not mobile, almost always entire, rarely distinctly 3-lobed, often with undulate margins.
India, Nepal, Bhutan, Burma, Thailand, Indochina, China, Taiwan, Japan, Malaysia, Brunei, the Philippines, Indonesia, Papua New Guinea. About 65 species; in New Guinea only one species (Dendrobium lancifolium).
Usually terrestrial in rather open vegetation among shrubs and grasses, or even fully exposed in secondary grassland (this applies to Dendrobium lancifolium; the great majority of species not occurring in New Guinea are epiphytes in lowland and lower montane forest).
Section Calcarifera attains its main development in Sumatra, Borneo, and the Philippines, with numerous, often quite beautiful species. In contrast, there is probably only one and rather atypical species in New Guinea, the magenta-purple flowered D. lancifolium. It seems that this only occurs in the extreme west of New Guinea, in particular the Vogelkop Peninsula and surrounding islands, while it is also rather common in the Moluccas and Sulawesi. In the large, spur-like mentum sect. Calcarifera resembles sect. Pedilonum, but, as Dauncey pointed out, the mentum is held parallel with the ovary in sect. Pedilonum, while it makes a rather large angle with the ovary in sect. Calcarifera.