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 reflexa

HABIT Perennial; short-lived; caespitose; clumped loosely. Butt sheaths herbaceous. Culms decumbent; 10–60 cm long. Culm-internodes terete. Leaves cauline. Leaf-sheaths with 0.33–0.66 of their length closed; keeled; smooth. Ligule an eciliate membrane; 1.5–3.5 mm long; glabrous on abaxial surface; entire, or erose, or lacerate; truncate, or obtuse. Leaf-blades flat, or conduplicate; 2–10 cm long; 1.5–4 mm wide; light green. Leaf-blade midrib keeled beneath. Leaf-blade surface glabrous. Leaf-blade apex hooded.

INFLORESCENCE Inflorescence a panicle.

Panicle open; pyramidal; nodding; 4–15 cm long; with spikelets clustered towards branch tips. Primary panicle branches spreading, or reflexed; 1–3 -nate. Panicle branches capillary; smooth.

Spikelets solitary. Fertile spikelets pedicelled.

FERTILE SPIKELETS Spikelets comprising 3–4 fertile florets; with diminished florets at the apex. Spikelets ovate; laterally compressed; 5–8 mm long; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes obscured by lemmas; smooth. Floret callus woolly.

GLUMES Glumes persistent; similar; shorter than spikelet. Lower glume oblong; 0.9 length of upper glume; membranous; 1-keeled; 1 -veined. Lower glume primary vein smooth, or scaberulous. Lower glume lateral veins absent. Lower glume apex acute. Upper glume lanceolate; membranous; 1-keeled; 1–3 -veined. Upper glume primary vein smooth, or scaberulous. Upper glume lateral veins absent, or obscure. Upper glume apex acute.

FLORETS Fertile lemma lanceolate; elliptic in profile; 3 mm long; membranous; keeled; 5 -veined. Lemma midvein ciliate; hairy all along. Lemma surface puberulous; hairy on veins. Lemma margins ciliate. Lemma apex acute. Palea 0.9 length of lemma. Palea keels scaberulous; adorned above. Apical sterile florets resembling fertile though underdeveloped.

FLOWER Lodicules 2; membranous. Anthers 3; 0.25–1 mm long; eventually exserted, or retained within floret.

FRUIT Caryopsis with adherent pericarp. Hilum punctiform.

DISTRIBUTION North America: northwest USA, north-central 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.