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.

Agrostis lacuna-vernalis

HABIT Annual; caespitose; clumped loosely. Basal innovations intravaginal. Culms erect, or geniculately ascending, or decumbent; slender; (1.5–)5–30 cm long; 0.25 mm diam.; 2–3 -noded. Culm-internodes smooth. Culm-nodes brown; glabrous. Lateral branches lacking. Leaves basal and cauline. Leaf-sheaths open for most of their length; mostly shorter than adjacent culm internode. Ligule an eciliate membrane; 1.2–1.7 mm long; erose; obtuse, or acute. Leaf-blades flat, or conduplicate, or involute; (1.4–)5–11 cm long; 0.3–1(–1.5) mm wide. Leaf-blade surface scabrous; rough abaxially; glabrous. Leaf-blade margins scaberulous.

INFLORESCENCE Inflorescence a panicle; comprising 12–90(–100) fertile spikelets.

Panicle spiciform; linear; 1–7.5 cm long; 0.1–0.6 cm wide. Primary panicle branches 1–3 -nate; 0.6–1.4 cm long. Panicle branches capillary; scabrous.

Spikelets solitary. Fertile spikelets pedicelled.

FERTILE SPIKELETS Spikelets comprising 1 fertile florets; without rhachilla extension. Spikelets elliptic; laterally compressed; 1.5–2.4 mm long; breaking up at maturity; disarticulating below each fertile floret.

GLUMES Glumes persistent; similar; exceeding apex of florets; firmer than fertile lemma; shiny. Lower glume ovate; 1.5–2.4 mm long; 1 length of upper glume; herbaceous, or scarious; 1-keeled; 1 -veined. Lower glume primary vein scaberulous. Lower glume lateral veins absent. Lower glume surface asperulous. Lower glume apex acute. Upper glume ovate; 1.5–2.4 mm long; herbaceous, or scarious; 1-keeled. Upper glume primary vein scaberulous. Upper glume surface scabrous. Upper glume margins scaberulous. Upper glume apex acute.

FLORETS Fertile lemma ovate; 1.1–1.5 mm long; hyaline; light green and purple (at tip); shiny; without keel; 5 -veined. Lemma midvein extending to apex. Lemma lateral veins obscure. Lemma surface smooth; glabrous. Lemma apex truncate, or obtuse; muticous. Palea 0.7–1.1 mm long; 0.5–0.66 length of lemma; hyaline. Palea apex obtuse.

FLOWER Lodicules 2; 0.4–0.5 mm long. Anthers 3; 0.4–0.7 mm long; yellow. Ovary glabrous.

FRUIT Caryopsis with adherent pericarp; ellipsoid; dorsally compressed; sulcate on hilar side; 0.9–1.2 mm long; light brown. Embryo 0.25 length of caryopsis. Hilum punctiform.

DISTRIBUTION North America: southwest USA.

NOTES Aveneae. Peterson & Soreng 2012.

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