Poa cusickii

HABIT Perennial; caespitose. Rhizomes short. Culms 20–40 cm long. Lateral branches lacking. Leaf-sheaths tubular for much of their length; with 0.5 of their length closed. Ligule an eciliate membrane; 1–3 mm long; erose; truncate. Leaf-blades flat, or involute; 10–20 cm long; 0.5–3.5 mm wide. Leaf-blade surface scabrous; glabrous.

INFLORESCENCE Inflorescence a panicle.

Panicle contracted; oblong, or ovate; 2–9 cm long; 1–2 cm wide. Panicle branches scaberulous.

Spikelets solitary. Fertile spikelets pedicelled.

FERTILE SPIKELETS Spikelets comprising 3–5 fertile florets; with diminished florets at the apex. Spikelets oblong; laterally compressed; 5–8 mm long; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes smooth. Floret callus glabrous, or woolly (slightly).

GLUMES Glumes persistent; similar; shorter than spikelet. Lower glume lanceolate; 3.5–5 mm long; 1 length of upper glume; membranous; 1-keeled; 3 -veined. Lower glume apex acute. Upper glume elliptic; 3.5–5 mm long; 0.8 length of adjacent fertile lemma; membranous; 1-keeled; 3 -veined. Upper glume apex acute.

FLORETS Fertile lemma ovate; elliptic in profile; 4.5–6 mm long; membranous; keeled; 5 -veined. Lemma midvein eciliate to ciliate. Lemma surface smooth to scabrous; pubescent; hairy on veins. Lemma apex acute. Palea 1 length of lemma. Palea keels ciliolate; adorned in the middle. Apical sterile florets resembling fertile though underdeveloped.

FLOWER Lodicules 2; membranous. Anthers 3; 2.2–3.2 mm long.

FRUIT Caryopsis with adherent pericarp. Hilum punctiform.

DISTRIBUTION North America: Subarctic, western Canada, northwest USA, north-central USA, and southwest USA.

NOTES Poeae. Fl Pac NW 1994.

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