Dendrobium somae Hayata, Icon. Pl. Formosan. 6: 71. 1916.小双花石斛 xiao shuang hua shi hu

Grastidium somae (Hayata) Rauschert.

Stems clustered, erect, cylindric, 60-100 cm, slender, 2-2.5 mm in diam., internodes 1-3 cm. Leaves alternate along upper part of stem, narrowly lanceolate, 7-10 × 0.5-0.6(or more) cm, base contracted and enlarged into sheath, apex acuminate; leaf sheath tubular, tightly embracing stem, jointed at junction with leaf blade. Inflorescence umbellate, lateral on leafy stems, 2-flowered; peduncle ca. 4 mm, with 1 basal sheath 1-1.7 cm. Flowers spreading; sepals and petals yellowish green, lip yellow. Dorsal sepal narrowly lanceolate, 13-17 × 2.5-3.5(or more) mm, 7-veined, long acuminate; lateral sepals similar but base oblique and adnate to column foot; mentum 4-6 mm. Petals linear, 13-15 × 1-2(or more) mm, 3-veined, long acuminate; lip ovate, 13-14 × 5-6.5(or more) mm, 3-lobed above middle; lateral lobes erect, oblong-triangular, acute; mid-lobe ovate, ca. 6 × 4 mm, long acuminate; disk glabrous, with 3 parallel stripes; mid-lobe veins forming fimbriate ridged projections. Column ca. 3 mm.

● Tree trunks in mountain forests; 500-1500 m. Taiwan (Hengchun, Taibei, Taidong).