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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.
Triplasis purpurea
HABIT Annual; caespitose. Culms geniculately ascending; 60–75 cm long; disarticulating at the nodes. Leaves cauline. Leaf-sheaths longer than adjacent culm internode. Ligule a fringe of hairs; 0.5–1 mm long. Leaf-blades 10–15 cm long; 2–4 mm wide. Leaf-blade midrib indistinct. Leaf-blade surface scabrous.
INFLORESCENCE Inflorescence a panicle; comprising 4–15 fertile spikelets.
Panicle open; ovate; 2–7 cm long; bearing few spikelets. Primary panicle branches simple; 1–2 cm long; bearing 1–4 fertile spikelets on each lower branch.
Spikelets solitary. Fertile spikelets pedicelled.
FERTILE SPIKELETS Spikelets comprising 2–3 fertile florets; with a barren rhachilla extension. Spikelets linear; laterally compressed; 6–8 mm long; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes 1.5 mm long; eventually visible between lemmas. Floret callus pubescent.
GLUMES Glumes persistent; similar; shorter than spikelet; similar to fertile lemma in texture. Lower glume linear; 2 mm long; 0.75 length of upper glume; membranous; 1-keeled; 1 -veined. Lower glume lateral veins absent. Lower glume apex dentate; 2 -fid. Upper glume lanceolate; 2.5–3 mm long; 0.75 length of adjacent fertile lemma; membranous; 1-keeled; 1 -veined. Upper glume lateral veins absent. Upper glume apex dentate; 2 -fid.
FLORETS Fertile lemma oblong; 3.6 mm long; membranous; keeled; 3 -veined. Lemma midvein pubescent. Lemma lateral veins close to margins. Lemma margins pubescent. Lemma apex dentate; 2 -fid; mucronate, or awned; 1 -awned. Principal lemma awn from a sinus; 0.5 mm long overall; limb pubescent; glabrescent towards tip. Palea bowed outwards; 0.75 length of lemma. Palea keels pubescent and with a crest of hairs. Rhachilla extension 0.5 length of fertile floret.
FLOWER Anthers 3; 2 mm long.
FRUIT Caryopsis with adherent pericarp; ellipsoid; laterally compressed; plano-convex; dark brown. Embryo projecting below grain.
CLEISTOGENES AND VIVIPARY Cleistogenes present; in lower sheaths.
DISTRIBUTION North America: eastern Canada, northwest USA, north-central USA, northeast USA, south-central USA, and southeast USA. South America: Mesoamericana.
NOTES Eragrostideae. Pohl.
Please cite this publication as detailed in How to Cite Version: 3rd February 2016.
