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.

Hilaria mutica

HABIT Perennial; caespitose. Rhizomes short. Culms erect; 30–50 cm long. Culm-internodes distally glabrous. Culm-nodes pubescent. Leaf-sheaths longer than adjacent culm internode; striately veined; antrorsely scabrous; outer margin glabrous, or hairy. Ligule an eciliate membrane; 1 mm long; lacerate. Leaf-blades flat, or involute; 5–10 cm long; 2–4 mm wide; stiff. Leaf-blade surface ribbed; scabrous; rough on both sides; glabrous, or pilose; hairy on both sides.

INFLORESCENCE Inflorescence composed of racemes.

Racemes borne along a central axis; closely spaced; in a multilateral false spike; cuneate; unilateral; 0.6–0.9 cm long; bearing a triad of spikelets. Central inflorescence axis 4–8 cm long. Rhachis obsolete; deciduous from axis. Raceme-bases brief; pilose.

Spikelets in threes. Fertile spikelets sessile; 1 in the cluster. Companion sterile spikelets sessile; 2 in the cluster.

STERILE SPIKELETS Companion sterile spikelets well-developed; male; cuneate; asymmetrical; dorsally compressed; 4–8 mm long; shorter than fertile; deciduous with the fertile. Companion sterile spikelet glumes free; membranous; 4–7 -veined; dentate; 2–7 -fid; muticous. Companion sterile spikelet lemmas 1–2; exserted from glumes; dentate; muticous.

FERTILE SPIKELETS Spikelets comprising 1 fertile florets; without rhachilla extension. Spikelets lanceolate; laterally compressed; 6–8 mm long; falling entire; deciduous with accessory branch structures.

GLUMES Glumes free; shorter than spikelet. Lower glume oblong; asymmetrical; membranous; pallid; 1-keeled; 7 -veined. Lower glume margins ciliolate. Lower glume apex lobed; 5 -fid; awned; 7 -awned. Lower glume awn terminal and dorsal; 1–2 mm long; ciliolate. Upper glume oblong; asymmetrical; 0.6–0.75 length of adjacent fertile lemma; membranous; pallid; 1-keeled; 7 -veined. Upper glume margins ciliolate. Upper glume apex lobed; 5 -fid; awned; 7 -awned. Upper glume awn terminal and dorsal; 1–2 mm long; ciliate.

FLORETS Fertile florets bisexual. Fertile lemma lanceolate; laterally compressed; 6–8 mm long; cartilaginous; keeled; 3 -veined. Lemma apex dentate; 2 -fid; obtuse; mucronate, or awned; 1 -awned. Principal lemma awn from a sinus; 1 mm long overall.

FLOWER Lodicules 2; 0.1–0.2 mm long. Anthers 3.

DISTRIBUTION North America: southwest USA, south-central USA, and Mexico.

NOTES Cynodonteae. Swallen.

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