GrassBase - The Online World Grass Flora

Descriptions

W.D. Clayton, M. Vorontsova, K.T. Harman & H. Williamson

© Copyright The Board of Trustees, Royal Botanic Gardens, Kew.

Poa hesperia

HABIT Perennial; mat forming. Rhizomes absent, or elongated. Butt sheaths grey, or light brown. Basal innovations intravaginal. Culms erect; 20–40 cm long. Lateral branches lacking. Leaves mostly basal. Leaf-sheaths smooth; glabrous on surface. Ligule an eciliate membrane; 0.5–1 mm long; scaberulous on abaxial surface; obtuse. Leaf-blades deciduous at the ligule; conduplicate; 5–10 cm long; 0.5–1 mm wide; coriaceous; firm; light green. Leaf-blade surface glabrous, or puberulous; hairy adaxially. Leaf-blade margins scaberulous.

INFLORESCENCE Inflorescence a panicle. Peduncle smooth.

Panicle open; ovate; 2–5.5 cm long. Primary panicle branches spreading; bearing 1–3 fertile spikelets on each lower branch. Panicle branches smooth, or scaberulous.

Spikelets solitary. Fertile spikelets pedicelled.

FERTILE SPIKELETS Spikelets comprising 4–8 fertile florets; with diminished florets at the apex. Spikelets oblong; laterally compressed; 4.5–10 mm long; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes 0.5 mm long; smooth. Floret callus woolly.

GLUMES Glumes persistent; similar; shorter than spikelet. Lower glume lanceolate; 2.5–3.5 mm long; 0.9–1 length of upper glume; membranous; 1-keeled; (1–)3 -veined. Lower glume primary vein smooth. Lower glume apex acute, or acuminate. Upper glume lanceolate; 3–4 mm long; 0.9 length of adjacent fertile lemma; membranous; 1-keeled; 3 -veined. Upper glume primary vein smooth. Upper glume apex acute, or acuminate.

FLORETS Fertile lemma elliptic; 3.5–4.5 mm long; membranous; keeled; 5 -veined. Lemma midvein ciliate; hairy below. Lemma surface puberulous; hairy at base; hairy on veins. Lemma margins ciliolate; hairy all along, or above. Lemma apex acute. Palea 2.5–4 mm long. Palea keels scabrous; adorned below. Palea surface smooth. Apical sterile florets resembling fertile though underdeveloped.

FLOWER Lodicules 2; 0.5 mm long; membranous. Anthers 3; 1.5–2.5 mm long.

FRUIT Caryopsis with adherent pericarp; 1 mm long. Hilum punctiform.

DISTRIBUTION Australasia: New Zealand.

NOTES Poeae. Edgar 1995.

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