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.

Hordeum pusillum

HABIT Perennial; caespitose. Culms geniculately ascending; 10–40 cm long. Culm-nodes brown; glabrous. Leaf-sheaths glabrous on surface, or pubescent. Leaf-sheath auricles absent, or falcate. Ligule an eciliate membrane; 0.5 mm long; truncate. Leaf-blades 3–12 cm long; 2–4 mm wide. Leaf-blade surface glabrous, or pubescent.

INFLORESCENCE Inflorescence composed of racemes.

Racemes 1; single; linear; bilateral; 4–8 cm long; 4–8 mm wide. Rhachis fragile at the nodes; flattened. Spikelet packing broadside to rhachis. Rhachis internodes oblong; falling with spikelet above.

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

STERILE SPIKELETS Companion sterile spikelets well-developed; containing empty lemmas, or male; linear; as long as fertile; deciduous with the fertile. Companion sterile spikelet glumes subulate; 8–15 mm long. Companion sterile spikelet lemmas 1; 1.5–3 mm long; 1-awned; with 1–2 mm long awn.

FERTILE SPIKELETS Spikelets comprising 1 fertile florets; with a barren rhachilla extension. Spikelets lanceolate; dorsally compressed; 4–6 mm long; falling entire; deciduous with accessory branch structures.

GLUMES Glumes collateral; similar; shorter than spikelet; gaping. Lower glume subulate; 7–15 mm long; 1 length of upper glume. Upper glume subulate; 7–15 mm long.

FLORETS Fertile lemma lanceolate; 4–6 mm long; coriaceous; without keel; 5 -veined. Lemma surface scabrous. Lemma apex acuminate; awned; 1 -awned. Principal lemma awn 2–7 mm long overall.

FLOWER Anthers 3. Ovary pubescent on apex.

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

DISTRIBUTION North America: western Canada, eastern Canada, northwest USA, north-central USA, northeast USA, southwest USA, south-central USA, southeast USA, and Mexico. South America: Caribbean, Brazil, and southern South America.

NOTES Triticeae. Gr Texas 1994.

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