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 chambersii

HABIT Perennial; caespitose. Rhizomes short. Butt sheaths persistent and investing base of culm. Culms geniculately ascending; 10–50 cm long; 0–2 -noded. Lateral branches ample. Leaf-sheaths tubular for much of their length; with 0.4–0.9 of their length closed; keeled. Ligule an eciliate membrane; 0.5–2 mm long; glabrous on abaxial surface; erose; truncate, or obtuse. Leaf-blades flat, or conduplicate; 4–8 cm long; 2–5 mm wide. Leaf-blade surface smooth; glabrous.

INFLORESCENCE Gynodioecious ("male", in this context, indicating the bisexual state), or dioecious. Inflorescence a panicle.

Panicle contracted; oblong, or ovate; 2–9 cm long; bearing few spikelets. Primary panicle branches ascending; 1–2 -nate; 1–3.5 cm long.

Spikelets solitary. Fertile spikelets pedicelled.

FERTILE SPIKELETS Spikelets comprising 2–7 fertile florets; with diminished florets at the apex. Spikelets ovate; laterally compressed; 6–12 mm long; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes smooth, or scaberulous. Floret callus glabrous, or woolly (slightly).

GLUMES Glumes persistent; similar; shorter than spikelet. Lower glume lanceolate; 3.5–4.5 mm long; 1 length of upper glume; membranous; 1-keeled; 3 -veined. Lower glume apex acute. Upper glume elliptic; 3.5–4.5 mm long; 0.6–0.8 length of adjacent fertile lemma; membranous; 1-keeled; 3 -veined. Upper glume apex acute.

FLORETS Fertile lemma ovate; 5–7 mm long; membranous; keeled; 5–7 -veined. Lemma midvein eciliate, or ciliolate; hairy below. Lemma margins eciliate, or ciliolate; hairy below. Lemma apex acute. Palea 1 length of lemma. Palea keels scabrous. Apical sterile florets resembling fertile though underdeveloped.

FLOWER Lodicules 2; 0.6 mm long; membranous. Anthers 3; 1.8–3.7 mm long.

FRUIT Caryopsis with adherent pericarp; 2 mm long. Hilum punctiform.

MALE Male spikelets resembling female.

DISTRIBUTION North America: northwest USA.

NOTES Poeae. Soreng 1999.

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