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 chaixii

HABIT Perennial; caespitose. Butt sheaths herbaceous. Basal innovations flabellate. Culms erect, or geniculately ascending; 60–120 cm long; 2–3 -noded. Culm-internodes terete; smooth. Lateral branches lacking. Leaves mostly basal. Leaf-sheaths keeled; smooth. Ligule an eciliate membrane; 0.5–1.5 mm long; truncate. Leaf-blades flat, or conduplicate; 15–45 cm long; 5–10 mm wide; light green. Leaf-blade venation with obscure cross veins. Leaf-blade surface smooth; glabrous. Leaf-blade margins scaberulous. Leaf-blade apex abruptly acute; hooded.

INFLORESCENCE Inflorescence a panicle. Peduncle smooth, or antrorsely scabrous above.

Panicle open; oblong, or ovate; effuse; equilateral, or nodding; 10–25 cm long; 5–12 cm wide. Primary panicle branches spreading, or drooping; 4–7 -nate. Panicle branches flexuous; scaberulous.

Spikelets solitary. Fertile spikelets pedicelled. Pedicels 0.5–3 mm long.

FERTILE SPIKELETS Spikelets comprising 3–4 fertile florets; with diminished florets at the apex. Spikelets oblong, or ovate; laterally compressed; 5–6 mm long; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes obscured by lemmas; smooth. Floret callus glabrous.

GLUMES Glumes persistent; similar; shorter than spikelet. Lower glume lanceolate; 2–3.5 mm long; 0.7–0.9 length of upper glume; membranous; 1-keeled; 1–3 -veined. Lower glume primary vein scabrous. Lower glume apex acute. Upper glume elliptic, or ovate; 3–4 mm long; 0.9–1 length of adjacent fertile lemma; membranous; 1-keeled; 3 -veined. Upper glume primary vein scabrous. Upper glume apex acute.

FLORETS Fertile lemma ovate; oblong in profile; 3.5–4 mm long; membranous; keeled; 5 -veined. Lemma surface asperulous. Lemma margins eciliate. Lemma apex acute. Palea 1 length of lemma. Palea keels scabrous. Apical sterile florets resembling fertile though underdeveloped.

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

FRUIT Caryopsis with adherent pericarp. Hilum punctiform.

DISTRIBUTION Europe: northern, central, southwestern, southeastern, and eastern. Asia-temperate: Caucasus and western Asia. North America: eastern Canada and north-central USA.

NOTES Poeae. CEH.

Please cite this publication as detailed in How to Cite Version: 27th January 2014.