Poa porsildii

HABIT Perennial; caespitose; clumped densely. Rhizomes absent. Stolons absent. Butt sheaths glabrous. Basal innovations intravaginal. Culms erect, or geniculately ascending; (12–)17–30(–40) cm long; 1–2 -noded. Leaf-sheaths open for most of their length; with 0.33–0.66 of their length closed. Ligule an eciliate membrane; 0.5–2 mm long; truncate, or obtuse. Collar glabrous. Leaf-blades conduplicate; 1–3 mm wide. Leaf-blade surface scaberulous; rough adaxially. Leaf-blade apex abruptly acute; hooded.

INFLORESCENCE Dioecious. Inflorescence a panicle; comprising 10–20 fertile spikelets.

Panicle open; ovate, or pyramidal; equilateral, or nodding; 2–5(–6) cm long. Primary panicle branches ascending, or spreading; 1–2 -nate; 2–4 cm long; bearing 1–3(–4) fertile spikelets on each lower branch. Panicle branches flexuous; smooth, or scaberulous.

Spikelets solitary. Fertile spikelets pedicelled.

FERTILE SPIKELETS Spikelets comprising 3–4 fertile florets; with diminished florets at the apex. Spikelets ovate; laterally compressed; 4–7 mm long; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes glabrous, or sparsely hairy. Floret callus glabrous.

GLUMES Glumes persistent; similar; shorter than spikelet. Lower glume lanceolate; 2.5 mm long; 0.6 length of upper glume; membranous; 1-keeled; 3 -veined. Lower glume primary vein smooth. Lower glume apex acute. Upper glume lanceolate; 4 mm long; 0.66–1 length of adjacent fertile lemma; membranous; 1-keeled; 3 -veined. Upper glume primary vein smooth. Upper glume apex acute.

FLORETS Fertile florets female. Fertile lemma elliptic; elliptic in profile; 4–6 mm long; membranous; keeled; 5 -veined. Lemma surface scaberulous; glabrous. Lemma apex acute. Palea keels scabrous; adorned above. Apical sterile florets resembling fertile though underdeveloped.

FLOWER Anthers 3; 2.5–3 mm long.

MALE Male inflorescence similar to female. Male spikelets resembling female.

DISTRIBUTION North America: Subarctic.

NOTES Poeae. Fl N Amer 2007.

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