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Descriptions

W.D. Clayton, M. Vorontsova, K.T. Harman & H. Williamson

© Copyright The Board of Trustees, Royal Botanic Gardens, Kew.

Orcuttia pilosa

HABIT Annual; caespitose. Culms erect, or geniculately ascending, or decumbent; 5–20(–35) cm long. Lateral branches lacking. Leaves without demarcation between sheath and blade. Leaf-sheaths viscid; pilose. Ligule absent. Leaf-blades 1–2 cm long; 3–5(–8) 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; crowded (above), or distant (below).

Spikelets solitary. Fertile spikelets sessile.

FERTILE SPIKELETS Spikelets comprising 10–40 fertile florets; with diminished florets at the apex. Spikelets ovate; laterally compressed; 10–15 mm long; breaking up at maturity; disarticulating below each fertile floret.

GLUMES Glumes persistent; similar; shorter than spikelet. Lower glume lanceolate; 3 mm long; 1 length of upper glume; chartaceous; without keels; 5–9 -veined. Lower glume apex dentate; 3 -fid. Upper glume lanceolate; 3 mm long; 0.5–0.75 length of adjacent fertile lemma; chartaceous; without keels; 5–9 -veined. Upper glume apex dentate; 3 -fid.

FLORETS Fertile lemma oblong; 4–5 mm long; chartaceous; keeled; 15 -veined. Lemma lateral veins prominent. Lemma apex lobed; 5 -fid; with simple equal lobes; incised 0.33–0.5 of lemma length; awned; 5 -awned. Principal lemma awn 0.5 mm long overall. Lateral lemma awns arising on apex of lobes; subequal to principal. Palea 1 length of lemma; 2 -veined. Apical sterile florets resembling fertile though underdeveloped.

FLOWER Lodicules absent. Anthers 3; 2.5–3 mm long; pallid. Stigmas 2; sparsely hairy.

FRUIT Caryopsis with adherent pericarp; ellipsoid; laterally compressed; 2 mm long; light brown; smooth. Embryo 0.75 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.