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 obvallata

HABIT Perennial. Rhizomes elongated. Butt sheaths dark brown; persistent and investing base of culm. Culms erect; 13–60 cm long. Culm-internodes antrorsely scabrous. Leaf-sheaths longer than adjacent culm internode; smooth, or antrorsely scabrous. Ligule an eciliate membrane; 5–10 mm long; acute. Leaf-blades curved; conduplicate; 2.5–10 cm long; 3.5–5 mm wide; coriaceous; stiff. Leaf-blade surface scabrous; rough adaxially, or on both sides. Leaf-blade apex pungent.

INFLORESCENCE Dioecious. Inflorescence a panicle; exserted, or embraced at base by subtending leaf.

Panicle contracted; oblong, or ovate; 4–8 cm long. Panicle branches scabrous.

Spikelets solitary. Fertile spikelets pedicelled.

FERTILE SPIKELETS Spikelets comprising 3–5 fertile florets; with diminished florets at the apex. Spikelets ovate; laterally compressed; 7.5–10 mm long; breaking up at maturity; disarticulating below each fertile floret. Floret callus woolly. Floret callus hairs 3–6 mm long; 0.5 length of lemma.

GLUMES Glumes persistent; similar; shorter than spikelet. Lower glume ovate; 5.5–7 mm long; 0.75 length of upper glume; membranous; 1-keeled; 3 -veined. Lower glume primary vein scabrous. Lower glume apex acute. Upper glume ovate; 6–8.5 mm long; 1 length of adjacent fertile lemma; membranous; 1-keeled; 3–5 -veined. Upper glume primary vein scabrous. Upper glume apex acute.

FLORETS Fertile florets female. Fertile lemma elliptic; elliptic in profile; 6–8 mm long; membranous; keeled; 5 -veined. Lemma midvein eciliate, or ciliolate; hairy below. Lemma margins ciliolate; hairy below. Lemma hairs 0.5 mm long. Lemma apex acute. Palea keels scabrous; ciliate; adorned in the middle. Apical sterile florets resembling fertile though underdeveloped.

FLOWER Lodicules 2; membranous. Anthers 3; 2.5–4.3 mm long. Staminodes present; 0.2–0.3 mm long. Stigmas 2–3.

FRUIT Caryopsis with adherent pericarp; trigonous; 3–3.5 mm long. Hilum punctiform.

MALE Male inflorescence similar to female. Male spikelets resembling female; 2–6 flowered; 5–9 mm long.

CLEISTOGENES AND VIVIPARY Vegetative proliferation occurs.

DISTRIBUTION South America: southern South America.

NOTES Poeae. Fl Pat 1995.

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