GrassBase - The Online World Grass Flora

Descriptions

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

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

Didymogonyx geminatum

HABIT Perennial; caespitose. Rhizomes short; pachymorph. Culms 20–25 mm diam.; woody. Culm-internodes terete; with small lumen; distally glabrous. Lateral branches dendroid. Bud complement 1. Branch complement in a clump; subtended by a bare patch above the node; with subequal branches. Culm-sheaths persistent. Leaf-sheaths glabrous on surface; outer margin hairy. Leaf-sheath oral hairs scanty, or ciliate; 2–3 mm long. Ligule absent. Leaf-blade base cuneate; with a brief petiole-like connection to sheath; petiole 0.2–0.3 cm long; petiole glabrous. Leaf-blades persistent; lanceolate; 5–9 cm long; 5–9 mm wide. Leaf-blade venation without cross veins. Leaf-blade surface glabrous. Leaf-blade margins scabrous. Leaf-blade apex acuminate.

INFLORESCENCE Inflorescence a panicle; comprising 18 fertile spikelets.

Panicle linear; 10.5 cm long. Primary panicle branches indistinct the panicle almost racemose.

Spikelets in pairs. Fertile spikelets sessile.

FERTILE SPIKELETS Spikelets comprising 5–6 fertile florets; with diminished florets at the apex. Spikelets oblong; laterally compressed; 15 mm long; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes clavate; 3 mm long; eventually visible between lemmas.

GLUMES Glumes two, or several; comprising 2–3 gemmiferous bracts; persistent; shorter than spikelet. Lower glume oblong, or ovate; 1.5–4 mm long; chartaceous; without keels, or 1-keeled; 1–3 -veined. Lower glume lateral veins absent, or distinct. Lower glume inner surface pubescent. Lower glume apex obtuse to acuminate; muticous. Upper glume oblong, or ovate; 2.5–4 mm long; 1-keeled; 3 -veined. Upper glume inner surface pubescent. Upper glume apex obtuse; muticous.

FLORETS Fertile lemma lanceolate; 7 mm long; chartaceous; without keel; 5 -veined. Lemma surface glabrous; inner surface pubescent. Lemma apex acute; muticous. Palea 1 length of lemma. Palea keels scabrous. Palea surface scabrous. Apical sterile florets resembling fertile though underdeveloped.

FLOWER Lodicules 3; 1 mm long. Anthers 3; 3.5 mm long. Stigmas 2. Ovary umbonate; glabrous.

FRUIT Caryopsis with adherent pericarp.

DISTRIBUTION South America: northern South America and western South America.

NOTES Bambuseae. McClure 1995.

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