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.

Orcuttia tenuis

HABIT Annual; culms solitary. Culms erect, or geniculately ascending; 5–15(–25) cm long. Lateral branches sparse; arising from upper culm. Leaves without demarcation between sheath and blade. Leaf-sheaths viscid. Ligule absent. Leaf-blades 1–2 cm long; 1.5–2 mm wide; viscid; aromatic. Leaf-blade surface pilose; sparsely hairy.

INFLORESCENCE Inflorescence composed of racemes.

Racemes 1; single; bilateral; 5–10 cm long. Rhachis angular. Spikelet packing broadside to rhachis; lax.

Spikelets solitary. Fertile spikelets sessile.

FERTILE SPIKELETS Spikelets comprising 5–20 fertile florets; with diminished florets at the apex. Spikelets ovate; laterally compressed; 12–15 mm long; breaking up at maturity; disarticulating below each fertile floret.

GLUMES Glumes persistent; similar; shorter than spikelet. Lower glume lanceolate; 3–6 mm long; 1 length of upper glume; chartaceous; without keels; 5–9 -veined. Lower glume apex dentate; 2–5 -fid. Upper glume lanceolate; 3–6 mm long; 0.75–1 length of adjacent fertile lemma; chartaceous; without keels; 5–9 -veined. Upper glume apex dentate; 2–5 -fid.

FLORETS Fertile lemma oblong; 4.5–6 mm long; chartaceous; keeled; 15 -veined. Lemma lateral veins prominent. Lemma apex lobed; 5 -fid; with simple equal lobes; incised 0.5 of lemma length; mucronate. Palea 1 length of lemma; 2 -veined. Apical sterile florets resembling fertile though underdeveloped.

FLOWER Lodicules absent. Anthers 3; 3 mm long; pallid. Stigmas 2; sparsely hairy.

FRUIT Caryopsis with adherent pericarp; oblong; laterally compressed; 3 mm long; light brown; smooth. Embryo 0.9 length of caryopsis.

DISTRIBUTION North America: southwest USA.

NOTES Orcuttieae. Reeder.

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