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.

Lachnagrostis tenuis

HABIT Annual; caespitose. Butt sheaths coriaceous; light brown. Basal innovations intravaginal. Culms 18–36 cm long. Leaf-sheaths smooth. Ligule a ciliolate membrane; 1–3.2 mm long; scaberulous on abaxial surface; erose; truncate. Leaf-blades involute; 2–12 cm long; 0.3–0.9 mm wide. Leaf-blade surface ribbed; grooved adaxially; scabrous; rough adaxially. Leaf-blade margins smooth. Leaf-blade apex obtuse.

INFLORESCENCE Inflorescence a panicle; deciduous as a whole; embraced at base by subtending leaf. Peduncle antrorsely scabrous above; fracturing.

Panicle open; elliptic; effuse; 6–12 cm long; 2–8 cm wide; with spikelets clustered towards branch tips. Primary panicle branches ascending, or spreading. Panicle branches capillary; scabrous.

Spikelets solitary. Fertile spikelets pedicelled.

FERTILE SPIKELETS Spikelets comprising 1 fertile florets; with a barren rhachilla extension. Spikelets lanceolate; laterally compressed; 3–5 mm long; breaking up at maturity; disarticulating below each fertile floret. Floret callus pubescent. Floret callus hairs 0.3–0.8 mm long; 0.25 length of lemma.

GLUMES Glumes persistent; similar; exceeding apex of florets; firmer than fertile lemma; gaping. Lower glume lanceolate, or elliptic; 1 length of upper glume; membranous; 1-keeled; 1(–3) -veined. Lower glume primary vein scabrous. Lower glume lateral veins absent, or obscure. Lower glume apex acuminate. Upper glume lanceolate, or elliptic; 3–5 mm long; 1.1 length of adjacent fertile lemma; membranous; 1-keeled; 1(–3) -veined. Upper glume primary vein scabrous. Upper glume lateral veins absent, or obscure. Upper glume apex acuminate.

FLORETS Fertile lemma lanceolate, or elliptic; 3–4.2 mm long; hyaline; without keel; 5 -veined. Lemma lateral veins excurrent. Lemma surface asperulous; glabrous. Lemma apex truncate; awned. Principal lemma awn dorsal; arising 0.33 way up back of lemma; geniculate; 3.5–6.5 mm long overall; with twisted column. Palea lanceolate; 2.5–3 mm long; 0.66 length of lemma; hyaline; 2 -veined. Palea keels scabrous. Rhachilla extension 1.5–2.5 mm long; pubescent; hairy throughout.

FLOWER Lodicules 2; lanceolate; 0.7–1 mm long; membranous; acute. Anthers 3; 0.7–0.9 mm long.

FRUIT Caryopsis with adherent pericarp; 1.4–1.6 mm long.

DISTRIBUTION Australasia: New Zealand.

NOTES Aveneae. Edgar 1997.

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