4. Dendrobium luzonense Lindley, Edwards’s Bot. Reg. 30(Misc.): 54. 1844.
吕宋石斛 lü song shi hu
Grastidium luzonense (Lindley) M. A. Clements & D. L. Jones.
Stems tufted, stiff, straight, to 7.5 cm, ca. 2.7 mm in diam., greenish brown, leafy in upper part, internodes 2.5-3.5 cm, loosely covered with leaf sheaths. Leaves linear, ca. 9 × 0.9 cm, base contracted, articulated with tubelike sheath, apex acuminate. Inflorescences lateral on leafy part of stem, 2-flowered, sessile. Pedicel and ovary ca. 1.1 cm. Flowers yellowish, lip brownish, central part yellow, glabrous, ca. 1.6 cm wide. Dorsal sepal oblong, ca. 9 × 4 mm, apex revolute; lateral sepals ca. 9 mm, ca. 7 mm wide at base, ± recurved; mentum ca. 4 mm. Petals oblong-lanceolate, ca. 8 × 3 mm, acute; lip 3-lobed, ca. 8.5 mm, glabrous, central part slightly ridged, basal part clawed and connate with column foot; mid-lobe oblong, 4-4.5 × ca. 3.5 mm, obtuse; lateral lobes triangular or toothlike, ca. 2 mm, acute. Column ca. 3 × 2 mm; foot ca. 4 mm; pollinia oblong.
Epiphytic on tree trunks and branches in forest bordering a creek; ca. 400 m. Taiwan (Taidong) [Philippines].
This species was first recorded from China by W. M. Lin, T. C. Hsu, and T. P. Lin (Taiwania 52: 284-286. 2007).