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 sterilis

HABIT Perennial; caespitose. Rhizomes elongated. Butt sheaths herbaceous. Culms erect; 25–40 cm long; with 0.5 of their length below uppermost node. Culm-internodes terete; smooth. Lateral branches lacking. Leaves mostly basal. Ligule an eciliate membrane; 1.5–3 mm long; truncate. Leaf-blades flat, or convolute; 3–15 cm long; 1–2 mm wide; flaccid. Leaf-blade surface smooth, or scabrous. Leaf-blade margins scabrous. Leaf-blade apex acuminate.

INFLORESCENCE Inflorescence a panicle.

Panicle open; lanceolate; 7–15 cm long; bearing few spikelets. Primary panicle branches ascending; 2–3 -nate. Panicle branches flexuous; scabrous.

Spikelets solitary. Fertile spikelets pedicelled.

FERTILE SPIKELETS Spikelets comprising (2–)3–4(–5) fertile florets; with diminished florets at the apex. Spikelets cuneate; laterally compressed; 4–6 mm long; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes smooth. Floret callus glabrous.

GLUMES Glumes persistent; similar; shorter than spikelet. Lower glume lanceolate, or elliptic; 3–4 mm long; 1 length of upper glume; membranous; 1-keeled; 3 -veined. Lower glume apex acute. Upper glume lanceolate, or elliptic; 3–4 mm long; 1 length of adjacent fertile lemma; membranous; 1-keeled; 3 -veined. Upper glume apex acute.

FLORETS Fertile lemma ovate; oblong in profile; 2.5–4(–5) mm long; membranous; keeled; 5 -veined. Lemma midvein ciliate. Lemma margins ciliate. Lemma apex obtuse. Palea 0.9 length of lemma. Palea keels scabrous. Apical sterile florets resembling fertile though underdeveloped.

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

FRUIT Caryopsis with adherent pericarp. Hilum punctiform.

DISTRIBUTION Europe: eastern. Asia-temperate: Caucasus and western Asia. Asia-tropical: India.

NOTES Poeae. Fl Pak.

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