Description from Flora of China
Aporum hainanense (Rolfe) Rauschert.
Stems rigid, ascending, compressed cylindric, slightly falcate, 10-30(-45) cm, 2-3 mm in diam., not branched, with many nodes, leafy throughout, internodes slightly clavate, ca. 1 cm. Leaf blade subcylindric, almost subulate, slender, 2-2.5(-5.5) × 0.1-0.3 cm, thickly fleshy, apex obtuse. Inflorescence arising from upper part of leafless stem, usually 1-flowered; floral bract ovate, ca. 1 mm, membranous. Pedicel and ovary ca. 6 mm, slender. Flower small, white with yellow spot on disk of lip. Dorsal sepal ovate, 3.3-4 × ca. 2.5 mm, 3-veined, apex subobtuse; lateral sepals ovate-triangular, 3.3-4 × ca. 3.5 mm, 3-veined, base oblique, apex acute; mentum ca. 10 mm. Petals narrowly oblong, 3.3-4 × ca. 1 mm, 1-veined, apex acute; lip obovate-triangular, ca. 15 × 7 mm, base clawed, apical margins undulate, apex emarginate; disk smooth. Column 1-1.5 mm, with a foot ca. 1 cm; anther cap semiglobose, glabrous. Fl. Sep-Oct.
Material in cultivation labeled "Dendrobium hainanense" with uniformly bright yellow flowers is incorrectly named; see the comment under D. hancockii (p. 385).
● On tree trunks in broad-leaved forests; 1000-1700 m. Hainan.