Oligostachyum gracilipes

HABIT Perennial. Culms erect; 200 cm long; 10 mm diam.; woody. Culm-internodes terete; hollow; purple; distally pilose; with reflexed hairs. Culm-nodes swollen; glabrous. Lateral branches dendroid. Branch complement three; with 1 branch dominant; thinner than stem. Culm-sheaths tardily deciduous; pubescent; with appressed hairs; with white hairs; without auricles; glabrous on shoulders. Culm-sheath ligule 2 mm high; entire, or ciliolate. Culm-sheath blade lanceolate; deciduous; erect, or spreading; scabrid; acuminate. Leaves cauline. Leaf-sheaths glabrous on surface; outer margin glabrous. Leaf-sheath oral hairs lacking. Ligule a ciliolate membrane; pubescent on abaxial surface; truncate. Leaf-blade base cuneate, or broadly rounded; with a brief petiole-like connection to sheath. Leaf-blades lanceolate, or oblong; 7–20 cm long; 10–20 mm wide. Leaf-blade venation with 8–10 secondary veins. Leaf-blade surface smooth, or scaberulous; rough abaxially. Leaf-blade margins scabrous. Leaf-blade apex acuminate.

INFLORESCENCE Synflorescence bractiferous; fasciculate; with spathaceous subtending bracts; bracts 20–90 mm long; 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 scabrous; glabrous, or pubescent.

FERTILE SPIKELETS Spikelets comprising 6–10 fertile florets; with diminished florets at the apex. Spikelets linear; laterally compressed; 40–60 mm long; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes clavate; curved; 4–6 mm long; pubescent.

GLUMES Glumes two; 2 empty glumes; persistent; similar; shorter than spikelet. Lower glume elliptic; 0.5–1 length of upper glume; chartaceous; 1-keeled. Lower glume surface scabrous. Lower glume apex acute. Upper glume elliptic; chartaceous; 1-keeled. Upper glume surface scabrous. Upper glume apex obtuse.

FLORETS Fertile lemma elliptic; 10–14 mm long; chartaceous; without keel. Lemma lateral veins with cross-veins. Lemma surface asperulous. Lemma margins ciliolate; hairy above. Lemma apex acute. Palea 8–9.5 mm long. Palea keels ciliate. Palea surface pubescent; hairy on back. Palea apex obtuse. Apical sterile florets resembling fertile though underdeveloped.

FLOWER Lodicules 3; ciliate. Anthers 3; 4–6 mm long; 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.