Dendrobium section Crumenata Pfitzer
in Engl. & Prantl, Nat. Pflanzenfam. II, 6 (1889) 174.
Rhizome short. Stems (much) elongated and slender, usually not branched, normally with several of the lower internodes conspicuously swollen and leafless, while the part above the swelling is very slender and many-leaved, often with the upper part with scale-like leaves only. Leaves sheathing at the base, glabrous, thick coriaceous, dorsiventrally flattened ('normal') or bilaterally flattened with sharp edges. Inflorescences arising laterally from the slender part of stem, but, if this is present, only from the scale-leaved upper part, very short, 1-flowered, often in small fascicles. Flowers rather small to rather large, lasting at most a few days, usually only one day, thin-textured. Mentum well-developed, not tubular in apical part. Lip not mobile.
India, Nepal, Bangladesh, Burma, Thailand, Indochina, China (Yunnan), Taiwan, Malaysia, Singapore, Brunei, the Philippines, Indonesia, Papua New Guinea, Australia, the Solomon Islands, Vanuatu, Fiji, Samoa. About 60 species; in New Guinea c. 8 species.
Epiphytes in lowland forest, usually growing in exposed positions.
Typical members of sect. Crumenata are easily recognised by the stems, which consist of two parts: a basal part of a few swollen, leafless internodes, and a much longer upper part which is very slender and leafy. Often, this slender part is again subdivided into two portions: a basal, leafy portion and a terminal portion covered in scale-leaves only; the flowers then emerge laterally from that bare terminal portion, which resembles an inflorescence. The leaves can be either dorsiventrally flattened, as in most orchids, or they can be laterally flattened or terete. The flowers are almost always short-lived, usually lasting less than a day. Unfortunately, as if to make life difficult for taxonomists, some New Guinea species agree in every respect with certain members of sect. Crumenata, but they lack the crucial detail of a swollen basal part to the stem. One of these is Dendrobium pseudocalceolum, which its author J.J. Smith assigned to sect. Aporum, while O'Byrne (calling it Dendrobium macfarlanei) tentatively placed it in sect. Strongyle. There can be little doubt that it is closely related to D. macfarlanei, which by its basal swelling is a bona fide member of sect. Crumenata. Perhaps this could be taken as evidence that these three sections should be merged. But to justify such a step more study should be devoted to this alliance within Dendrobium (and then sect. Bolbidium should also be considered). Some species of sect. Crumenata have very pretty flowers, especially those in the group with dorsiventrally flattened leaves, but on the whole this section has had very little impact in horticulture.