Dendrobium section Oxystophyllum (Blume) Miq.,
Fl. Ned. Indië 3 (1859) 645.
Rhizome short, roots (unlike sect. Aporum) brown, very thin. Stems short to much elongated and slender, branched or not, not fleshy, densely many-leaved throughout. Leaves sheathing at the base, overlapping, glabrous, thick coriaceous, bilaterally flattened, with sharp edges and sharp pointed apex. Inflorescences arising laterally from the stem, very short, 1-flowered, often in small clusters. Flowers small, lasting at least several days, often rather fleshy, usually dark maroon, sometimes greenish or yellowish. Mentum well-developed, not tubular in apical part. Lip not mobile, at the apex on the abaxial side with a pointed swelling.
Burma, Thailand, Indochina, Malaysia, Singapore, Brunei, the Philippines, Indonesia, Papua New Guinea, Solomon islands. About 30 species; in New Guinea c. 10 species.
Epiphytes in lowland and lower montane forest.
While section Oxystophyllum appears similar to species of sect. Aporum because of the overlapping, laterally flattened leaves, it is apparent from molecular studies that it is not closely related. In fact, molecular analyses independently performed by M. A. Clements and Y. P. Ng suggest that sect. Oxystophyllum does not even belong to the genus Dendrobium, but rather to the genus Eria! In hindsight, this is corroborated by several morphological characters, such as the wiry brown roots. It is true that Eria should have eight pollinia, while Dendrobium always has four pollinia. Sect. Oxystophyllum clearly has four pollinia, but they lack the typical shape of Dendrobium pollinia, which are always quite narrow and cohering in two pairs, while they are much thicker and less clearly paired in Oxystophyllum. Fortunately, these revolutionary developments will have little effect outside the realm of taxonomy, since the ornamental qualities of sect. Oxystophyllum are negligable. The small flowers, often mercifully hidden on the underside of the stems, are most often very deep maroon, but they can also be greenish tinged with dull red. The lip is provided with a more or less conical wart on the underside near its apex.