燕石斛 yan shi hu

Aporum equitans (Kraenzlin) Brieger; Ceraia batanensis (Ames & Quisumbing) M. A. Clements; C. equitans (Kraenzlin) M. A. Clements; Dendrobium batanense Ames & Quisumbing.

Stems erect, cylindric, compressed, to 40 cm, 1 or 2 internodes above base dilated and fusiform, 2-3 cm. Leaves distichous, ascending, laterally compressed and dagger-shaped, 4-7 cm × 3-4(or more) mm, fleshy, base with tightly clasping fleshy sheaths, apex acute. Inflorescence axillary in distal leaf axil; floral bracts sheathlike, ca. 4 mm, membranous. Pedicel and ovary ca. 1 cm. Flowers usually solitary, each lasting 1 or 2 days, not opening widely, creamy white, disk yellow in center. Dorsal sepal ovate-lanceolate, ca. 15 mm, ca. 3.5 mm wide at middle, acute; lateral sepals obliquely ovate-lanceolate, nearly as long as dorsal sepal, base oblique; mentum angulate, 8-10 mm. Petals obovate-lanceolate, nearly as large as dorsal sepal, 3-veined, apex acute; lip obovate, ca. 18 mm, ca. 9 mm wide at middle, 3-lobed above middle, base cuneate; lateral lobes erect, subobovate, front margin denticulate; mid-lobe orbicular or transversely oblong, margin lacerate or fimbriate, apex rounded; disk densely finely papillate-hairy. Column ca. 2 mm; anther cap subquadrate, glabrous.

Epiphytic on tree trunks in forests; 100-300 m. S Taiwan (Lan Yu) [Philippines].

This species has been misidentified in Taiwan as Dendrobium ventricosum Kraenzlin (e.g., in Fl. Taiwan. 5: 969. 1978).