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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.
Poa costiniana
HABIT Perennial; caespitose; clumped densely. Butt sheaths herbaceous; pallid. Basal innovations intravaginal. Culms erect; 15–80 cm long; 1–2 -noded. Culm-internodes terete; smooth. Culm-nodes glabrous. Lateral branches lacking. Leaf-sheaths smooth; glabrous on surface. Ligule a ciliolate membrane; 1–3 mm long; pubescent on abaxial surface; truncate, or obtuse. Leaf-blades convolute; 7–40 cm long; 0.3–1.75 mm wide. Leaf-blade surface scabrous; rough adaxially; glabrous. Leaf-blade apex abruptly acute.
INFLORESCENCE Inflorescence a panicle. Peduncle smooth.
Panicle open; pyramidal; 5–20 cm long. Primary panicle branches spreading; 2–5 -nate. Panicle branches capillary; scabrous.
Spikelets solitary. Fertile spikelets pedicelled. Pedicels scabrous.
FERTILE SPIKELETS Spikelets comprising 2–5 fertile florets; with diminished florets at the apex. Spikelets ovate; laterally compressed; 6–10 mm long; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes smooth. Floret callus glabrous, or woolly.
GLUMES Glumes persistent; similar; shorter than spikelet. Lower glume oblong; 0.9 length of upper glume; membranous; 1-keeled; 1–3 -veined. Lower glume primary vein scabrous. Lower glume lateral veins absent, or obscure. Lower glume surface smooth, or asperulous. Lower glume apex acute, or acuminate. Upper glume oblong; membranous; 1-keeled; 3(–5) -veined. Upper glume primary vein scabrous. Upper glume surface smooth, or asperulous. Upper glume apex acute, or acuminate.
FLORETS Fertile lemma lanceolate; elliptic in profile; 3.5–5.5 mm long; membranous; keeled; 5 -veined. Lemma midvein scabrous; ciliate; hairy below. Lemma surface smooth, or scaberulous; rough on veins; pubescent; hairy on veins. Lemma margins ciliolate; hairy at base. Lemma apex acute. Palea 0.9 length of lemma. Palea keels scabrous; ciliolate; adorned in the middle. Apical sterile florets resembling fertile though underdeveloped.
FLOWER Lodicules 2; membranous. Anthers 3; 2–2.6 mm long; yellow, or purple.
FRUIT Caryopsis with adherent pericarp; oblong; 2.5 mm long. Hilum punctiform.
CLEISTOGENES AND VIVIPARY Vegetative proliferation occurs.
DISTRIBUTION Australasia: Australia.
NOTES Poeae. Vickery.
Please cite this publication as detailed in How to Cite Version: 3rd February 2016.