镇沅石斛 Dendrobium zhenyuanense

Other specimen examined:—CHINA. Yunnan Province: Lincang County, on tree, broad-leaved evergreen forest,1900 m, 27 September 2012, Li 2244 (HITBC!). 

Epiphytic herbs, produced in Lincang County, Yunnan Province.
Plants are short. Stem fleshy, fusiform, 1.0-1.8 cm long, 4-5 mm in diameter, 2-3 nodes, current-year stem surrounded by leaf sheath, former stem bare, dark purple.
Leaves two rows, 2-3, alternate, shorter in lower part of stem than in upper part, lanceolate, 1. 5-2. 0 × 0. 4-0. 6 cm, apex obtuse and unequally 2-lobed, base enlarged into sheath, sheath opening obliquely truncated and enclosed stem.
Racemes 1-3, erect, subterminal or lateral in upper part of current-year stem, usually 1. 0-1. 7 cm, not higher than leaves, with numerous flowers ; shaft slender, 2 cm long, ca. 0.5 mm in diameter ; bracts lanceolate, ca. 1.0-2.0 × 0.5 mm, membranous, apex acute. Flowers green, pedicel and ovary 1-2 mm long ; middle sepals narrowly ovate, ca. 3.5 × 1.0 mm, three-veined, apex acute ; lateral sepals ovate-triangular, ca. 3.5 × 1.5 mm, three-veined, apex acute, apex viscid ; the calyx sac is oblong, 1.0-1.5 mm long. Petals lanceolate, 3 × 1 mm, three veins, apex acute. Lip flap elliptic, ca. 2.5 × 1.5 mm, apex acute ; the base has two semicircular lamellae, and the top is thickened and fleshy ; stigma is about 2 mm long, base enlarged ; the top edge of the cap is slightly nicked.        Flowering : July-August.

Epiphytic herbs with smooth roots. Stems fusiform, 1.0–1.8 cm long, 4–5 mm in diam., with 2–3 nodes, current stems enclosed in leaf sheaths, previous stems naked, dark purple. Leaves 2–3, distichous, lowermost smaller than upper, lanceolate, 1.5–2.0 × 0.4–0.6 cm, base dilated into sheaths, mouth of which is obliquely truncate and enclosing the stem, apex obtuse and unequally bilobed. Inflorescences 1–3, subterminal or lateral on upper part of current year’s stem, erect, usually 1.0–1.7 cm, not exceeding leaves, several flowered; rachis slender, 2 cm long, ca. 0.5 mm in diam.; floral bracts lanceolate, ca. 1.0–2.0 ×0.5 mm, membranous, apex acute. Flowers green, pedicel and ovary 1–2 mm long; dorsal sepal narrowly ovate, ca. 3.5 × 1.0 mm, triveined, apex acute; lateral sepals ovate-triangular, ca. 3.5× 1.5mm, triveined, apex acute, tip with a distinct mucro; mentum oblong, 1.0–1.5 mm long. Petals lanceolate, 3 ×1mm, triveined, apex acute. Lip elliptic, ca. 2.5 × 1.5 mm, apex acute; base with two semi-rotund lamellae, tip much thickened and fleshy; column ca. 2 mm long, base dilated; anther cap with apical margin slightly lacerate.