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 perennis

HABIT Perennial; caespitose; clumped densely. Culms erect, or geniculately ascending; 20–60 cm long; 0.5–1.5 mm diam.; 2–3 -noded. Culm-internodes terete; striate, or ridged; smooth. Lateral branches lacking. Leaf-sheaths open for most of their length; with 0.25–0.5 of their length closed; 4–10 cm long; smooth, or scaberulous; glabrous on surface, or pilose; with reflexed hairs. Leaf-sheath oral hairs scanty, or lacking. Ligule an eciliate membrane; 0.5–2 mm long; erose; truncate. Leaf-blades flat, or conduplicate; 5–10 cm long; 1–2 mm wide. Leaf-blade surface smooth, or scabrous; glabrous; hairless throughout, or except near base. Leaf-blade margins scabrous.

INFLORESCENCE Inflorescence a panicle.

Panicle open; pyramidal; 6–13 cm long; 2–7 cm wide. Primary panicle branches 2–3 -nate; 2–8 cm long; bearing 3–10 fertile spikelets on each lower branch. Panicle axis with lower internodes 1.4–3.5 cm long. Panicle branches flexuous; terete, or angular; scabrous; rough distally.

Spikelets solitary. Fertile spikelets pedicelled.

FERTILE SPIKELETS Spikelets comprising 2–4 fertile florets; with diminished florets at the apex. Spikelets oblong, or ovate; laterally compressed; 4–7 mm long; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes 1.2 mm long; smooth, or scaberulous. Floret callus glabrous, or sparsely hairy.

GLUMES Glumes persistent; similar; shorter than spikelet. Lower glume lanceolate; 2–2.5 mm long; 0.8 length of upper glume; membranous; purple; 1-keeled; 3 -veined. Lower glume primary vein smooth. Lower glume lateral veins absent. Lower glume apex acuminate. Upper glume lanceolate; 4.7–5.5 mm long; 0.75 length of adjacent fertile lemma; membranous; purple; 1-keeled; 3 -veined. Upper glume primary vein scabrous; eciliate, or ciliolate. Upper glume apex acute.

FLORETS Fertile lemma lanceolate; elliptic in profile; 3.3–4.8 mm long; membranous; keeled; 5 -veined. Lemma midvein ciliolate. Lemma lateral veins obscure. Lemma surface scabrous; glabrous. Lemma margins scaberulous; eciliate, or ciliolate; hairy above. Lemma apex acute, or acuminate. Palea keels scabrous; adorned above. Palea surface smooth, or scaberulous. Apical sterile florets resembling fertile though underdeveloped.

FLOWER Lodicules 2; membranous. Anthers 3; 1.5–2.3 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.