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.

Arthrostylidium punctulatum

HABIT Perennial; caespitose. Rhizomes short; pachymorph. Culms scandent; 400–700 cm long; 5–10 mm diam.; woody. Culm-internodes terete; hollow; 18–51 cm long. Lateral branches dendroid; intravaginal. Bud complement 1. Branch complement several; in a clump; subtended by a bare patch above the node; with subequal branches; thinner than stem. Culm-sheaths persistent; 7.5–15 cm long; 2.5–3 times as long as wide; green and purple; distinctly mottled with last colour; glabrous. Culm-sheath ligule 0.5 mm high. Culm-sheath blade triangular; demarcated but persistent; erect; 5–11 cm long; 18–32 mm wide; pubescent and with ciliate margins. Leaves 4–6(–9) per branch. Leaf-sheaths striately veined; papillose; glabrous on surface; outer margin glabrous, or hairy. Leaf-sheath oral hairs setose; curly; 6–10 mm long; pale. Ligule a ciliolate membrane; 0.8–1 mm long; pubescent on abaxial surface. Collar with external ligule. Leaf-blade base with a brief petiole-like connection to sheath; petiole 0.4–0.7 cm long; petiole pubescent. Leaf-blades ovate; 10–22 cm long; 20–40 mm wide. Leaf-blade midrib indistinct. Leaf-blade venation with distinct cross veins. Leaf-blade surface glabrous, or pilose; hairy abaxially. Leaf-blade apex acuminate.

INFLORESCENCE Inflorescence composed of racemes.

Racemes 1; single; straight; bilateral; 10–15 cm long; bearing few fertile spikelets; bearing 4–8 fertile spikelets on each. Rhachis pilose on surface. Spikelet packing broadside to rhachis. Rhachis internodes 6–26 mm long.

Spikelets solitary. Fertile spikelets sessile.

FERTILE SPIKELETS Spikelets comprising 5–10 fertile florets; with diminished florets at the apex. Spikelets linear; laterally compressed; 25–50 mm long; 3–6 mm wide; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes 3–5 mm long; pilose.

GLUMES Glumes two, or several; 2–3 empty glumes; persistent; similar; shorter than spikelet. Lower glume ovate; 3.5–5.5 mm long; chartaceous; without keels. Lower glume primary vein scabrous. Lower glume surface glabrous. Lower glume margins ciliate. Lower glume apex acute. Upper glume ovate; 6.5–8 mm long; without keels; 7–9 -veined. Upper glume surface glabrous. Upper glume margins ciliate. Upper glume apex acute; mucronate.

FLORETS Fertile lemma ovate; 9–10.5 mm long; 4–5 mm wide; chartaceous; without keel; 7–10 -veined. Lemma surface rugulose; without grooves; glabrous. Lemma margins ciliolate. Lemma apex acute; mucronate. Palea 8–9.5 mm long; 3 -veined. Palea keels ciliolate. Apical sterile florets 1 in number; rudimentary.

FLOWER Lodicules 3; 2–4 mm long; veined; ciliate. Anthers 3; 2–2.5 mm long. Stigmas 2.

FRUIT Caryopsis with adherent pericarp.

DISTRIBUTION South America: western South America.

NOTES Bambuseae. Lord & Clarke 2001.

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