Oligostachyum scopulum

HABIT Perennial. Culms erect; 300–500 cm long; 15 mm diam.; woody. Culm-internodes terete; hollow; distally mealy. Culm-nodes swollen; glabrous. Lateral branches dendroid; erect, or ascending. Branch complement three; with 1 branch dominant; thinner than stem. Culm-sheaths tardily deciduous; pubescent; hairy at the base; with reflexed hairs; glabrous on margins, or hairy on margins; without auricles; glabrous on shoulders. Culm-sheath ligule 1–2 mm high; entire, or ciliolate. Culm-sheath blade lanceolate; deciduous; erect, or reflexed; pubescent. Leaves cauline; 5–9 per branch. Leaf-sheaths striately veined; glabrous on surface. Leaf-sheath oral hairs lacking. Ligule a ciliolate membrane; scaberulous on abaxial surface; truncate. Leaf-blade base simple, or broadly rounded; with a brief petiole-like connection to sheath; petiole glabrous. Leaf-blades lanceolate, or oblong; 5.5–17 cm long; 8–21 mm wide. Leaf-blade surface glabrous. Leaf-blade margins scabrous. Leaf-blade apex acuminate.

INFLORESCENCE Synflorescence bractiferous; fasciculate; with spathaceous subtending bracts; without axillary buds at base of spikelet; with ultimate bract subtending a compact bracteolate fascicle of spikelets; prophyllate below lateral spikelets.

Fertile spikelets pedicelled. Pedicels 5–15 mm long; glabrous to pubescent.

FERTILE SPIKELETS Spikelets comprising 6–8 fertile florets; with diminished florets at the apex. Spikelets linear; laterally compressed; 40–70 mm long; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes curved; 4–5 mm long; pilose; hairy at tip.

GLUMES Glumes several; 4–6 empty glumes; persistent; similar; shorter than spikelet. Lower glume lanceolate; 2.5–4.5 mm long; chartaceous; 1-keeled. Lower glume primary vein ciliolate. Lower glume apex acute. Upper glume lanceolate; 2.5–4.5 mm long; chartaceous; 1-keeled. Upper glume primary vein ciliolate. Upper glume apex acute.

FLORETS Fertile lemma elliptic; 7.5–9 mm long; chartaceous; without keel. Lemma lateral veins obscure. Lemma apex obtuse; mucronate. Palea keels ciliate. Palea surface pubescent; hairy on back. Palea apex obtuse. Apical sterile florets resembling fertile though underdeveloped.

FLOWER Lodicules 3; 2–3 mm long; ciliate. Anthers 3; anther tip smooth. Stigmas 3. Ovary umbonate; glabrous.

FRUIT Caryopsis with adherent pericarp.

DISTRIBUTION Asia-temperate: China.

NOTES Arundinarieae. McClure 1996.

Please cite this publication as detailed in How to Cite Version: 3rd February 2016.