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 pruinosum

HABIT Perennial; caespitose. Rhizomes elongated. Culms 50–80 cm long. Leaf-sheaths outer margin glabrous, or hairy. Ligule an eciliate membrane; 3–4 mm long; 1–2 mm long on basal shoots; acute. Leaf-blades filiform; convolute; 20–25 cm long; 1.1–1.5 mm wide; 1.5 cm long at summit of culm; stiff; glaucous. 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 cartilaginous.

INFLORESCENCE Inflorescence a panicle; comprising 10–16 fertile spikelets.

Panicle open; linear, or oblong; 7–13 cm long. Primary panicle branches 1–2 -nate; bearing 1 fertile spikelets on each lower branch.

Spikelets solitary. Fertile spikelets pedicelled.

FERTILE SPIKELETS Spikelets comprising 5–7 fertile florets; with diminished florets at the apex. Spikelets oblong; laterally compressed; 22–30 mm long; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes 3 mm long; pubescent; with 0.6 mm long hairs. Floret callus pubescent. Floret callus hairs 1 mm long.

GLUMES Glumes persistent; similar; shorter than spikelet; thinner than fertile lemma. Lower glume elliptic; 14–17 mm long; 0.75 length of upper glume; membranous; 1-keeled; 3 -veined. Lower glume apex acute. Upper glume elliptic; 17–20 mm long; 1.1–1.2 length of adjacent fertile lemma; membranous; 1-keeled; 3 -veined. Upper glume apex acute.

FLORETS Fertile lemma elliptic; widest at 0.5 of its length from base; 14–18 mm long; cartilaginous; without keel; 5–7 -veined. Lemma apex dentate; 2 -fid; awned; 1 -awned. Principal lemma awn dorsal; arising 0.5 way up back of lemma; geniculate; flat below; 18–24 mm long overall; with twisted column. Palea keels ciliolate. Apical sterile florets resembling fertile though underdeveloped.

FLOWER Anthers 3. 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.