GrassBase - The Online World Grass Flora


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

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

Bambusa riauensis

HABIT Perennial; caespitose. Rhizomes short; pachymorph. Culms erect; pendulous at the tip; 800–1000 cm long; 20–30 mm diam.; woody; without nodal roots. Culm-internodes terete; hollow; 45–55 cm long; mid-green and yellow; striped; distally glabrous, or hispid. Lateral branches dendroid; arising from mid culm. Bud complement 1. Branch complement several; in a clump; with 1 branch dominant; thinner than stem. Culm-sheaths persistent, or deciduous; 12.6–13.5 cm long; 2 times as long as wide; hispid; with white hairs, or black hairs; truncate at apex; auriculate; setose on shoulders; shoulders with 7 mm long hairs. Culm-sheath ligule 3–4 mm high; entire, or ciliolate. Culm-sheath blade triangular; narrower than sheath; erect; 7–12.4 cm long; 2.5–3 mm wide; glabrous on surface. Leaf-sheath oral hairs lacking. Leaf-sheath auricles erect; 0.3–0.5 mm long. Ligule an eciliate membrane; 3 mm long. Collar with external ligule. Leaf-blade base with a brief petiole-like connection to sheath. Leaf-blades deciduous at the ligule; lanceolate; 15–26 cm long; 16–30 mm wide. Leaf-blade surface glabrous. Leaf-blade margins ciliate. Leaf-blade apex acuminate.

INFLORESCENCE Synflorescence bractiferous; clustered at the nodes; in untidy tufts; with spathaceous subtending bracts; with axillary buds at base of spikelet; prophyllate below lateral spikelets; leafless between clusters.

FERTILE SPIKELETS Spikelets comprising 4 fertile florets; with diminished florets at the apex. Spikelets lanceolate; laterally compressed; 10–15 mm long; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes definite; 1–3 mm long; glabrous.

GLUMES Glumes several; 3 empty glumes; persistent; similar; shorter than spikelet; similar to fertile lemma in texture. Lower glume ovate; 4 mm long. Lower glume apex acute. Upper glume ovate; 6 mm long. Upper glume apex acute.

FLORETS Fertile lemma ovate; 8–9 mm long; without keel. Lemma apex acute. Palea 8–9 mm long. Palea apex acute. Apical sterile florets resembling fertile though underdeveloped.

FLOWER Lodicules 3; membranous; ciliate. Anthers 6; 5–6 mm long; yellow. Stigmas 3. Ovary glabrous.

FRUIT Caryopsis with adherent pericarp.

DISTRIBUTION Asia-tropical: Malesia.

NOTES Bambuseae. Widjaja 2002.

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