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.

Psathyrostachys rupestris

HABIT Perennial; caespitose. Butt sheaths grey; glabrous. Culms 20–70 cm long; 3–4 -noded. Culm-internodes distally glabrous. Leaf-sheath oral hairs lacking. Leaf-sheath auricles falcate. Ligule an eciliate membrane; 0.2–0.4 mm long. Leaf-blades flat, or involute; 2.5–6.5 cm long; 0.8–2.8 mm wide. Leaf-blade surface smooth, or scabrous; rough adaxially; glabrous. Leaf-blade margins scabrous.

INFLORESCENCE Inflorescence composed of racemes. Peduncle glabrous.

Racemes 1; single; linear, or oblong; bilateral; 2.5–6.5 cm long; 5–10 mm wide. Rhachis fragile at the nodes; ciliate on margins. Spikelet packing broadside to rhachis. Rhachis internodes cuneate; 2–4 mm long; falling with spikelet above.

Spikelets in pairs, or in threes. Fertile spikelets sessile; 2–3 in the cluster; the central smaller (8–13mm).

FERTILE SPIKELETS Spikelets comprising 1–2 fertile florets; with a barren rhachilla extension. Spikelets lanceolate; dorsally compressed; 9–16 mm long; 1.1–1.5 mm wide; falling entire; deciduous with accessory branch structures.

GLUMES Glumes collateral; similar; exceeding apex of florets; gaping. Lower glume subulate; 9–16 mm long; 1 length of upper glume. Lower glume surface scabrous; glabrous, or pilose. Lower glume hairs 0.6–1 mm long. Upper glume subulate; 9–16 mm long. Upper glume surface scabrous; glabrous, or pilose. Upper glume hairs 0.6–1 mm long.

FLORETS Fertile lemma lanceolate; 6.7–11.6 mm long; coriaceous; without keel; 7 -veined. Lemma surface glabrous, or pilose. Lemma hairs 0.6–1 mm long. Lemma apex acuminate; awned; 1 -awned. Principal lemma awn 4.7–8.5 mm long overall; limb smooth, or scabrous. Palea coriaceous. Palea keels scaberulous. Palea surface glabrous, or pilose. Rhachilla extension 3–5 mm long.

FLOWER Anthers 3–4 mm long; yellow. Ovary pubescent on apex.

FRUIT Caryopsis with adherent pericarp; 4–6.5 mm long. Hilum linear.

DISTRIBUTION Asia-temperate: Caucasus.

NOTES Triticeae. Baden 1992.

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