Poa orba

HABIT Perennial. Rhizomes elongated. Basal innovations extravaginal. Culms 5–15 cm long. Culm-internodes terete, or elliptical in section; distally glabrous. Lateral branches lacking. Leaves mostly basal. Leaf-sheaths open for most of their length; with 0.1 of their length closed; smooth; glabrous on surface. Ligule an eciliate membrane; 0.9–3.5 mm long; pubescent on abaxial surface; acute. Leaf-blades conduplicate; 4–8 cm long; 0.8–1.5 mm wide; stiff; grey-green. Leaf-blade surface puberulous; hairy adaxially. Leaf-blade apex acute; hooded.

INFLORESCENCE Inflorescence a panicle.

Panicle open, or contracted; oblong, or ovate; 2–6 cm long. Panicle branches scabrous.

Spikelets solitary. Fertile spikelets pedicelled.

FERTILE SPIKELETS Spikelets comprising (2–)3–5 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. Floret callus glabrous.

GLUMES Glumes persistent; similar; shorter than spikelet. Lower glume ovate; 1.9–2.7 mm long; 0.9 length of upper glume; membranous; 1-keeled; 1–3 -veined. Lower glume lateral veins absent, or obscure. Lower glume apex acute. Upper glume ovate; 2.1–2.9 mm long; 0.9 length of adjacent fertile lemma; membranous; 1-keeled; 3–5 -veined. Upper glume apex acute.

FLORETS Fertile lemma oblong; elliptic in profile; 2.3–3.2 mm long; membranous; keeled; 5 -veined. Lemma midvein without distinctive roughness, or scaberulous (at tip). Lemma surface glabrous. Palea 1 length of lemma. Palea keels scabrous; adorned above. Apical sterile florets resembling fertile though underdeveloped.

FLOWER Anthers 3; 1.2–1.6 mm long.

FRUIT Caryopsis with adherent pericarp. Hilum punctiform.

DISTRIBUTION Australasia: Australia.

NOTES Poeae. Walsh 2007.

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