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.

Hordeum comosum

HABIT Perennial; caespitose. Butt sheaths purple; persistent and investing base of culm; with compacted dead sheaths. Culms 10–70 cm long. Leaf-sheaths pubescent. Leaf-sheath auricles absent, or falcate. Ligule a ciliolate membrane; 0.5 mm long; truncate. Leaf-blades flat, or convolute; 3–5 cm long; 1–2 mm wide. Leaf-blade surface pubescent; hairy on both sides.

INFLORESCENCE Inflorescence composed of racemes; exserted, or embraced at base by subtending leaf.

Racemes 1; single; bilateral; 4–10 cm long. Rhachis fragile at the nodes; flattened; glabrous on margins, or ciliate on margins. Spikelet packing broadside to rhachis. Rhachis internodes oblong; 1–2 mm long; falling with spikelet above.

Spikelets in threes. Fertile spikelets sessile; 1 in the cluster. Companion sterile spikelets pedicelled; 2 in the cluster. Pedicels oblong; 1–1.5 mm long.

STERILE SPIKELETS Companion sterile spikelets well-developed; containing empty lemmas; lanceolate; dorsally compressed; 20–30 mm long; shorter than fertile, or as long as fertile; deciduous with the fertile. Companion sterile spikelet glumes similar in width; subulate; 20–30 mm long. Companion sterile spikelet lemmas 1; 10–17 mm long; 1-awned; with 7–12 mm long awn.

FERTILE SPIKELETS Spikelets comprising 1 fertile florets; with a barren rhachilla extension. Spikelets lanceolate; dorsally compressed; 20–35 mm long; falling entire; deciduous with accessory branch structures.

GLUMES Glumes collateral; similar; exceeding apex of florets; gaping. Lower glume subulate; 20–35 mm long; 1 length of upper glume; coriaceous. Lower glume surface scabrous. Upper glume subulate; 20–35 mm long; coriaceous. Upper glume surface scabrous.

FLORETS Fertile lemma lanceolate; 7–15 mm long; coriaceous; yellow, or purple; without keel; 5 -veined. Lemma surface scaberulous; rough above. Lemma apex acuminate; awned; 1 -awned. Principal lemma awn 15–25 mm long overall. Palea 6–10.5 mm long. Palea surface scabrous. Rhachilla extension 2.5–6 mm long.

FLOWER Lodicules 2; 1–2 mm long; ciliate. Anthers 3; 2–4.3 mm long. Ovary pubescent on apex.

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

DISTRIBUTION South America: southern South America. Antarctic: Subantarctic islands.

NOTES Triticeae. Fl Pat 1995.

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