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.

Helictotrichon tenuifolium

HABIT Perennial; caespitose. Basal innovations extravaginal. Culms 30–45 cm long; 0.5–1 mm diam. Culm-nodes purple. Ligule an eciliate membrane; 1–2 mm long; acute. Leaf-blades straight; filiform; 2–7 cm long; 0.3–0.4 mm wide; 0.3–0.4 cm long at summit of culm. Leaf-blade midrib indistinct. Leaf-blade venation with subepidermal sclerenchyma free from veins; without layer of subepidermal sclerenchyma masking vein striation. Leaf-blade surface ungrooved; scabrous. Leaf-blade margins unthickened.

INFLORESCENCE Inflorescence a panicle; comprising 2–8 fertile spikelets.

Panicle open; linear; 4–18 cm long. Primary panicle branches indistinct the panicle almost racemose.

Spikelets solitary. Fertile spikelets sessile.

FERTILE SPIKELETS Spikelets comprising 4–9 fertile florets; with diminished florets at the apex. Spikelets oblong; laterally compressed; 14–15 mm long; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes 1.5–2 mm long; glabrous. Floret callus pubescent. Floret callus hairs 0.8–1 mm long.

GLUMES Glumes persistent; similar; shorter than spikelet; thinner than fertile lemma. Lower glume elliptic; 7–8 mm long; 0.75–0.85 length of upper glume; membranous; 1-keeled; 3 -veined. Lower glume apex acute. Upper glume elliptic; 9 mm long; 1 length of adjacent fertile lemma; membranous; 1-keeled; 3 -veined. Upper glume apex acute.

FLORETS Fertile lemma elliptic; widest at 0.66 of its length from base; 9–10 mm long; cartilaginous; without keel; 5 -veined. Lemma surface pubescent; hairy below. Lemma apex dentate; 2 -fid; obtuse; awned; 1 -awned. Principal lemma awn dorsal; arising 0.5–0.66 way up back of lemma; geniculate; flat below; 10–15 mm long overall; with twisted column. Palea keels ciliolate. Apical sterile florets resembling fertile though underdeveloped.

FLOWER Anthers 3; 3–6 mm long. Ovary pubescent on apex.

FRUIT Caryopsis with adherent pericarp; hairy at apex. Hilum linear.

DISTRIBUTION Europe: southwestern.

NOTES Aveneae. Fl Eur 1995.

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