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Descriptions

W.D. Clayton, M. Vorontsova, K.T. Harman & H. Williamson

© Copyright The Board of Trustees, Royal Botanic Gardens, Kew.

Helictotrichon tianschanicum

HABIT Perennial; caespitose; clumped densely. Butt sheaths persistent and investing base of culm; with compacted dead sheaths. Culms 14–30 cm long. Culm-internodes distally glabrous. Leaf-sheaths puberulous. Ligule a ciliolate membrane; 0.2 mm long. Leaf-blades 1.5–3 mm wide. Leaf-blade surface smooth; glabrous.

INFLORESCENCE Inflorescence a panicle.

Panicle open; oblong; 4–8 cm long; bearing few spikelets.

Spikelets solitary. Fertile spikelets pedicelled.

FERTILE SPIKELETS Spikelets comprising 2–3 fertile florets; with diminished florets at the apex. Spikelets oblong; laterally compressed; 9–10 mm long; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes pilose; with 2–3 mm long hairs. Floret callus pilose.

GLUMES Glumes persistent; similar; shorter than spikelet; thinner than fertile lemma. Lower glume lanceolate; 8–9 mm long; 0.9 length of upper glume; membranous; 1-keeled; 3 -veined. Lower glume apex acute. Upper glume lanceolate; 9–10 mm long; 1 length of adjacent fertile lemma; membranous; 1-keeled; 5 -veined. Upper glume apex acute.

FLORETS Fertile lemma lanceolate; 9–10 mm long; cartilaginous; without keel; 5–7 -veined. Lemma apex dentate; 2 -fid; awned; 1 -awned. Principal lemma awn dorsal; arising 0.66 way up back of lemma; geniculate; 10–15 mm long overall; with twisted column. 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 Asia-temperate: Soviet Middle Asia and China.

NOTES Aveneae. Fl USSR 1995.

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