GrassBase - The Online World Grass Flora


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

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

Poa binodis

HABIT Perennial; caespitose; clumped loosely. Rhizomes elongated. Basal innovations extravaginal, or intravaginal. Culms erect; 10–90 cm long; 2 -noded. Culm-internodes smooth. Lateral branches lacking. Leaf-sheaths open for most of their length; with 0.66 of their length closed; 7–16 cm long; with winged keel; smooth; pilose, or hispid. Leaf-sheath oral hairs lacking, or pubescent, or ciliate. Ligule an eciliate membrane; 1–2 mm long. Leaf-blades conduplicate, or involute; 4–10 cm long; 3 mm wide; coriaceous. Leaf-blade surface smooth, or scaberulous; rough on both sides.

INFLORESCENCE Inflorescence a panicle.

Panicle contracted; lanceolate; loose; 12–20 cm long; 3–5 cm wide. Primary panicle branches 2–3 -nate; 3–9 cm long; bearing 10–17 fertile spikelets on each lower branch. Panicle branches smooth, or scaberulous.

Spikelets solitary. Fertile spikelets pedicelled. Pedicels 0.5–1 mm long; 2 mm long at branch tip.

FERTILE SPIKELETS Spikelets comprising 3–6 fertile florets; with diminished florets at the apex. Spikelets oblong, or ovate; laterally compressed; 3.5–7 mm long; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes 0.5–1.5 mm long; scaberulous. Floret callus glabrous.

GLUMES Glumes persistent; similar; shorter than spikelet. Lower glume lanceolate; 2–2.5 mm long; 0.75 length of upper glume; membranous; 1-keeled; 3 -veined. Lower glume primary vein smooth. Lower glume lateral veins absent. Lower glume surface asperulous. Lower glume apex acuminate. Upper glume lanceolate; 2.8–3.5 mm long; 0.9 length of adjacent fertile lemma; membranous; 1-keeled; 3 -veined. Upper glume primary vein scabrous. Upper glume surface asperulous. Upper glume apex acute.

FLORETS Fertile lemma lanceolate; 3–4 mm long; membranous; keeled; 5(–7) -veined. Lemma midvein scabrous. Lemma lateral veins prominent; less than two thirds length of lemma. Lemma surface smooth; puberulous. Lemma margins eciliate. Lemma apex acute. Palea keels scabrous; with 0.3–0.5 of their length adorned; with 30–50 enations per keel. Apical sterile florets resembling fertile though underdeveloped.

FLOWER Lodicules 2; membranous. Anthers 3; 2 mm long.

FRUIT Caryopsis with adherent pericarp. Hilum punctiform.

DISTRIBUTION Asia-temperate: China.

NOTES Poeae. Fl China 2005.

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