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 stepparia

HABIT Perennial; caespitose. Rhizomes elongated. Basal innovations intravaginal. Culms 50–70 cm long. Leaf-sheaths tubular for much of their length; with 1 of their length closed; longer than adjacent culm internode; antrorsely scabrous. Ligule an eciliate membrane; truncate. Leaf-blades conduplicate; 1–11 cm long; 3.5–6 mm wide; stiff. Leaf-blade surface scabrous; rough adaxially. Leaf-blade margins scabrous. Leaf-blade apex pungent.

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

Panicle open; lanceolate; 7–15 cm long. Primary panicle branches 2.5–6.5 cm long. Panicle branches smooth, or scaberulous.

Spikelets solitary. Fertile spikelets pedicelled.

FERTILE SPIKELETS Spikelets comprising 2–4 fertile florets; with diminished florets at the apex. Spikelets ovate; laterally compressed; 6.5–8 mm long; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes 0.6–1 mm long. Floret callus pubescent.

GLUMES Glumes persistent; similar; shorter than spikelet. Lower glume ovate; 4.3–5 mm long; 0.9 length of upper glume; membranous; 1-keeled; 3 -veined. Lower glume primary vein smooth. Lower glume apex acute. Upper glume ovate; 5–5.5 mm long; 0.75–0.9 length of adjacent fertile lemma; membranous; 1-keeled; 3 -veined. Upper glume primary vein smooth. Upper glume apex acute.

FLORETS Fertile florets female. Fertile lemma ovate; 5.5–7 mm long; membranous; keeled; 5 -veined. Lemma midvein ciliate; hairy below. Lemma lateral veins obscure. Lemma margins eciliate, or ciliate; hairy below. Lemma apex acute. Palea keels ciliolate. Apical sterile florets resembling fertile though underdeveloped.

FLOWER Lodicules 2; membranous. Anthers 3; 3–3.5 mm long. Staminodes present; 1.5 mm long.

FRUIT Caryopsis with adherent pericarp; trigonous; sulcate on hilar side; 2–2.5 mm long; dark brown. Hilum punctiform.

MALE Male inflorescence similar to female. Male spikelets resembling female.

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.