Opizia bracteata

HABIT Annual; mat forming. Culms slender; 4–15 cm long. Leaf-sheaths outer margin hairy. Leaf-sheath oral hairs ciliate. Ligule a ciliolate membrane; 0.5 mm long. Leaf-blades linear, or triangular; 1–4(–7) cm long; 1–2(–3) mm wide. Leaf-blade surface glabrous; hairless except near base.

INFLORESCENCE Monoecious; with male and female spikelets in different inflorescences. Inflorescence composed of racemes; bracteate at pedicel base (2 linear bracts, 3–4mm); embraced at base by subtending leaf.

Racemes 1–3; single, or borne along a central axis; unilateral; 1–2 cm long; bearing 1–4 fertile spikelets on each. Rhachis of lateral racemes deciduous from axis; angular; 0.5 mm wide; terminating in a barren extension; extension subulate; extension 2–4 mm long. Spikelet packing lax.

Spikelets solitary. Fertile spikelets sessile. Male spikelets sessile.

FERTILE SPIKELETS Spikelets comprising 1 fertile florets; with diminished florets at the apex. Spikelets cuneate; laterally compressed; 3–3.5 mm long; falling entire.

GLUMES Glumes reaching apex of florets; thinner than fertile lemma. Lower glume lanceolate; 1.8 mm long; 0.5 length of upper glume; hyaline. Lower glume apex acute. Upper glume oblong; 3–3.5 mm long; 1 length of adjacent fertile lemma; membranous; without keels; 1 -veined. Upper glume lateral veins absent. Upper glume surface pilose. Upper glume apex obtuse.

FLORETS Fertile florets female. Fertile lemma ovate; 3–3.5 mm long; coriaceous; much thinner above; pallid; keeled; 3 -veined. Lemma lateral veins prominent. Lemma surface pilose; hairy below. Lemma apex entire; obtuse; muticous. Palea fused below to rhachilla internode; 3.5–4 mm long; cartilaginous; 2 -veined. Rhachilla extension 1 mm long. Apical sterile florets 1 in number; lanceolate; 1–2 mm long. Apical sterile lemmas awned; 3 -awned (the central winged at base). Apical sterile lemma awns 5 mm long; 3 per spikelet in number.

FLOWER Anthers 2 mm long; yellow, or orange. Stigmas terminally exserted.

MALE Male inflorescence terminal; unlike female; of racemes along a central axis; with pectinate racemes. Male spikelets distinct from female; 1 flowered; lanceolate; 4 mm long; glabrous. Male spikelet glumes 2; linear; 1–3 mm long. Male spikelet lemma 3.5 mm long; 3 -veined; muticous.

DISTRIBUTION North America: Mexico.

NOTES Cynodonteae. Fl Nov Gal 1997.

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