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.

Leymus yiunensis

HABIT Perennial; caespitose; clumped loosely. Rhizomes elongated. Butt sheaths persistent and investing base of culm; with compacted dead sheaths. Culms erect; 25–35 cm long. Culm-internodes distally glabrous. Leaf-sheaths glabrous on surface; outer margin glabrous, or hairy. Ligule an eciliate membrane; 1 mm long; truncate. Leaf-blades flat, or involute; 4–9 cm long; 1–2 mm wide; coriaceous; stiff. Leaf-blade surface scabrous; rough adaxially. Leaf-blade margins scabrous. Leaf-blade apex attenuate.

INFLORESCENCE Inflorescence composed of racemes.

Racemes 1; single; erect; bilateral; 5–11 cm long; 5–10 mm wide. Rhachis flattened; ciliate on margins. Spikelet packing broadside to rhachis. Rhachis internodes 3–7 mm long.

Spikelets in pairs. Fertile spikelets sessile; 2 in the cluster.

FERTILE SPIKELETS Spikelets comprising 3–8 fertile florets; with diminished florets at the apex. Spikelets elliptic; laterally compressed; 7–11 mm long; breaking up at maturity; disarticulating below each fertile floret. Rhachilla internodes 1–1.5 mm long; pubescent. Floret callus pubescent. Floret callus hairs 0.5–1 mm long.

GLUMES Glumes persistent; similar; shorter than spikelet. Lower glume lanceolate; 5–8 mm long; 0.9 length of upper glume; 1 -veined. Lower glume lateral veins obscure. Lower glume surface pubescent. Lower glume apex setaceously attenuate. Upper glume lanceolate; 8–9 mm long; 1–1.1 length of adjacent fertile lemma; 1 -veined. Upper glume lateral veins absent. Upper glume surface pubescent. Upper glume margins ciliate. Upper glume apex setaceously attenuate.

FLORETS Fertile lemma lanceolate; 7–9 mm long; coriaceous; without keel; 5 -veined. Lemma surface pubescent; hairy all along. Lemma margins ciliate. Lemma apex acute; awned; 1 -awned. Principal lemma awn 1 mm long overall. Palea 1 length of lemma. Palea keels ciliate. Apical sterile florets resembling fertile though underdeveloped.

FLOWER Anthers 3; 3 mm long; yellow. Stigmas 2. Ovary pubescent on apex.

FRUIT Caryopsis with adherent pericarp. Hilum linear.

DISTRIBUTION Asia-temperate: China.

NOTES Triticeae. Cui 2006.

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