Bulbophyllum rivulare Schltr., Repert. Spec. Nov. Regni Veg. Beih. 1 (1913) 784
Type: Schlechter 19778 (holo B, lost)
Epiphyte, very small. Rhizome short. Roots filiform, flexuose, glabrous. Pseudobulbs obliquely ovoid, 4-6 mm by 0.3-0.4 cm below the middle; 1-leaved. Leaf erect, ligulate, obtuse, glabrous, 1.2-2.3 by 0.4-0.6 cm near the middle; base narrowed. Inflorescence 1-flowered, filiform, with a few small peduncle-scales. Floral bracts very small, much shorter than the pedicellate ovary. Flower erect. Sepals narrowly lanceolate, acute, glabrous. Median sepal 1.2 cm long. Lateral sepals oblique, c. 1.35 cm long. Petals broadly ovate, glabrous, 0.3 cm long; apex terminating in a semiorbicular, finely warty lobule. Lip curved, fleshy, ovate tongue-shaped, obtuse, as long as the petals. Column short; stelidia triangular, acute, sublobulate. Anther reniform-cordate, umbonate, glabrous. Pedicel and ovary slender, glabrous, 1.5-2 cm long. (After Schlechter, 1913)
Colours: Flower whitish. Median sepal spotted red all over. Lateral sepals spotted red only at the base. Petals with 2 rows of red spots. Lip spotted red. Column golden yellow.
Habitat: Epiphyte in lower montane forest; terrestrial on shale; 1300-2400 m.
Flowering time in the wild: February, June, October.
Distribution: Malesia (New Guinea).
Distribution in New Guinea: Papua (Indonesia); Papua New Guinea; see map 96-1593M.jpg.
Cultivation: Intermediate growing epiphyte.