Poa palmeri

HABIT Perennial; caespitose; clumped loosely, or moderately, or densely. Cataphylls evident. Rhizomes absent, or short. Butt sheaths papery; glabrous. Basal innovations extravaginal, or intravaginal. Culms erect, or geniculately ascending; slender; (26–)50–70 cm long; 3–4 -noded. Culm-internodes terete. Lateral branches lacking. Leaf-sheaths tubular for much of their length; with 0.3–0.7 of their length closed; (5–)17–18 cm long; smooth, or scaberulous; glabrous on surface, or pilose; with reflexed hairs. Ligule an eciliate membrane, or a ciliolate membrane; 0.8–3 mm long; hyaline, or scarious; scaberulous on abaxial surface; entire, or erose, or lacerate; truncate, or obtuse. Leaf-blades flat, or involute; 2–30 cm long; (1.5–)2–3 mm wide; 2.5–10.8 cm long at summit of culm. Leaf-blade margins scabrous. Leaf-blade apex abruptly acute; hooded.

INFLORESCENCE Bisexual (mostly, but some spikelets male or female). Inflorescence a panicle; comprising (18–)40–100 fertile spikelets.

Panicle open; pyramidal; 6.5–20 cm long. Primary panicle branches spreading, or reflexed; (1–)2–4(–5) -nate; 4–10 cm long; bearing 3–34 fertile spikelets on each lower branch. Panicle branches flexuous; terete, or angular; scabrous.

Spikelets solitary. Fertile spikelets pedicelled. Pedicels 0.5–1 length of fertile spikelet; scabrous.

FERTILE SPIKELETS Spikelets comprising (2–)3–6(–9) fertile florets; with diminished florets at the apex. Spikelets lanceolate; laterally compressed; 3–8 mm long; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes terete; 1 mm long; smooth, or scaberulous. Floret callus woolly. Floret callus hairs 1–2 mm long.

GLUMES Glumes persistent; similar; shorter than spikelet. Lower glume lanceolate; 1.6–3.5 mm long; 0.75 length of upper glume; membranous; 1-keeled; 1 -veined. Lower glume lateral veins absent. Lower glume apex acute. Upper glume lanceolate; 2.2–4.9 mm long; 0.9 length of adjacent fertile lemma; membranous; 1-keeled; 3 -veined. Upper glume apex acute.

FLORETS Fertile lemma lanceolate; 2.6–5 mm long; membranous; keeled; 5 -veined. Lemma midvein ciliate; hairy below. Lemma lateral veins obscure, or distinct. Lemma surface smooth, or scaberulous; rough on veins. Lemma margins ciliate; hairy below. Lemma apex acute. Palea keels approximate; 0.3–0.4 mm apart; eciliate, or puberulous. Palea surface scabrous. Apical sterile florets resembling fertile though underdeveloped.

FLOWER Lodicules 2; lanceolate; 0.5 mm long; with a small lateral lobe. Anthers 3; 1.6–2.8 mm long.

FRUIT Caryopsis with adherent pericarp; ellipsoid; 1.6–2.8 mm long; rugose. Hilum punctiform. Disseminule comprising a caryopsis and palea.

DISTRIBUTION North America: Mexico.

NOTES Poeae. Soreng & Peterson 2012.

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