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Descriptions

W.D. Clayton, M. Vorontsova, K.T. Harman & H. Williamson

© Copyright The Board of Trustees, Royal Botanic Gardens, Kew.

Oligostachyum oedogonatum

HABIT Perennial. Rhizomes elongated; leptomorph. Culms 450 cm long; 8 mm diam.; woody. Culm-internodes terete; 33 cm long; dark green, or grey; distally mealy. Culm-nodes with distinct supra-nodal ridge. Lateral branches dendroid. Branch complement several; with subequal branches. Culm-sheaths purple; pubescent; auriculate; setose on shoulders. Culm-sheath ligule 3 mm high; entire. Culm-sheath blade linear, or lanceolate; erect, or spreading. Leaves 2–3 per branch. Leaf-sheaths glabrous on surface. Leaf-sheath oral hairs setose. Leaf-sheath auricles falcate. Ligule an eciliate membrane; 2 mm long; obtuse. Leaf-blade base with a brief petiole-like connection to sheath. Leaf-blades linear, or lanceolate; 13–25 cm long; 7–39 mm wide. Leaf-blade venation with 10–16 secondary veins. Leaf-blade surface glabrous. Leaf-blade apex acuminate.

INFLORESCENCE Inflorescence composed of racemes; bracteate at branch bases.

Racemes 1; single; 4–6 cm long; bearing few fertile spikelets; bearing 2–3 fertile spikelets on each.

Spikelets solitary. Fertile spikelets pedicelled. Pedicels 15 mm long; glabrous, or pubescent.

FERTILE SPIKELETS Spikelets with diminished florets at the apex. Spikelets linear; laterally compressed; 15–50 mm long; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes 2–3.5 mm long; pubescent.

GLUMES Glumes two, or several; 1–3 empty glumes; persistent; similar; shorter than spikelet. Lower glume lanceolate; chartaceous. Upper glume ovate; 11 mm long; chartaceous; 7–9 -veined.

FLORETS Fertile lemma ovate; 13–16 mm long; chartaceous; without keel; 7–11 -veined. Lemma surface pilose. Lemma margins ciliate. Lemma apex setaceously attenuate. Palea 8–10 mm long. Palea keels ciliate; adorned above; with 0.66 of their length adorned. Palea apex emarginate, or obtuse. Apical sterile florets resembling fertile though underdeveloped.

FLOWER Lodicules 3. Anthers 3(–5); 4–5 mm long. Stigmas 3.

DISTRIBUTION Asia-temperate: China.

NOTES Arundinarieae. Fl China 2006.

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