Poa laxiflora

HABIT Perennial; culms solitary. Rhizomes elongated. Culms erect; 90–120 cm long. Culm-internodes retrorsely scabrous. Lateral branches lacking. Leaf-sheaths tubular for much of their length; with 0.5 of their length closed; keeled; retrorsely scabrous. Ligule an eciliate membrane; 1–3 mm long; scaberulous on abaxial surface; erose; truncate. Leaf-blades 2–5 mm wide. Leaf-blade surface scabrous; rough on both sides. Leaf-blade apex abruptly acute; hooded.

INFLORESCENCE Inflorescence a panicle.

Panicle open; pyramidal; 12–20 cm long. Primary panicle branches spreading, or reflexed; 2–3 -nate. Panicle branches scabrous.

Spikelets solitary. Fertile spikelets pedicelled.

FERTILE SPIKELETS Spikelets comprising 3–4 fertile florets; with diminished florets at the apex. Spikelets oblong; laterally compressed; 5–6 mm long; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes smooth. Floret callus woolly.

GLUMES Glumes persistent; similar; shorter than spikelet. Lower glume lanceolate; 3 mm long; 0.9 length of upper glume; membranous; 1-keeled; 3 -veined. Lower glume primary vein scabrous. Lower glume apex acute. Upper glume elliptic; 3.5 mm long; 0.9 length of adjacent fertile lemma; membranous; 1-keeled; 3 -veined. Upper glume primary vein scabrous. Upper glume apex acute.

FLORETS Fertile lemma ovate; elliptic in profile; 4 mm long; membranous; keeled; 5 -veined. Lemma midvein pubescent. Lemma lateral veins obscure. Lemma surface pubescent; hairy on veins. Lemma margins pubescent. Lemma apex acute. Palea 1 length of lemma. Palea keels scabrous; adorned above. Apical sterile florets resembling fertile though underdeveloped.

FLOWER Lodicules 2; membranous. Anthers 3; 1 mm long.

FRUIT Caryopsis with adherent pericarp. Hilum punctiform.

DISTRIBUTION North America: Subarctic and northwest USA.

NOTES Poeae. Fl Pac NW 1994.

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