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 interior

HABIT Perennial; caespitose; clumped densely. Butt sheaths herbaceous. Culms erect; 5–50 cm long; wiry; with 0.33–0.66 of their length below uppermost node. Culm-internodes terete; smooth. Lateral branches lacking. Ligule a ciliolate membrane; 1–2 mm long; scaberulous on abaxial surface; truncate, or obtuse. Leaf-blades 6–15 cm long; 1–2.5 mm wide. Leaf-blade surface glabrous.

INFLORESCENCE Inflorescence a panicle. Peduncle smooth, or scaberulous above.

Panicle open; pyramidal; 2–15 cm long. Primary panicle branches ascending; 2 -nate; sparsely divided; 3–6 cm long. Panicle branches scabrous.

Spikelets solitary. Fertile spikelets pedicelled.

FERTILE SPIKELETS Spikelets comprising 2–3 fertile florets; with diminished florets at the apex. Spikelets ovate; laterally compressed; 2.5–5 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; incurved at apex, or recurved at apex. Lower glume oblong; 0.9 length of upper glume; membranous; 1-keeled; 3 -veined. Lower glume primary vein scaberulous. Lower glume apex acute. Upper glume lanceolate; membranous; 1-keeled; 3 -veined. Upper glume primary vein scaberulous. Upper glume apex acute.

FLORETS Fertile lemma oblong; elliptic in profile; 2.5–3.5 mm long; membranous; keeled; 5 -veined. Lemma midvein ciliate; hairy all along. Lemma lateral veins with distinct primaries but obscure intermediates. Lemma surface papillose; pubescent; hairy on veins. Lemma margins ciliate. Lemma apex obtuse. Palea 0.9 length of lemma. Palea keels scaberulous; adorned all along. Apical sterile florets resembling fertile though underdeveloped.

FLOWER Lodicules 2; membranous. Anthers 3; 1.1–1.8 mm long.

FRUIT Caryopsis with adherent pericarp. Hilum punctiform.

DISTRIBUTION North America: western Canada, eastern Canada, northwest USA, north-central USA, northeast USA, southwest USA, and south-central USA.

NOTES Poeae. Soreng 1992.

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