Andropogon angustatus

HABIT Perennial; caespitose. Culms erect; 20–100 cm long; 1–1.5 mm diam. Culm-nodes glabrous. Lateral branches ample. Ligule an eciliate membrane; 1–2.5 mm long; brown. Leaf-blades flat, or conduplicate; 15–30 cm long; 1.5–3 mm wide. Leaf-blade surface glabrous.

INFLORESCENCE Synflorescence compound; paniculate. Inflorescence composed of racemes; terminal and axillary; subtended by a spatheole. Spatheole linear; 5–7 cm long.

Racemes 2; paired; 2–4 cm long. Rhachis fragile at the nodes; ciliate on margins. Rhachis hairs 0.5–1 mm long. Rhachis internodes cuneate; 2–2.5 mm long. Rhachis internode tip transverse; crateriform; with simple rim.

Spikelets squeezed between internode and pedicel; in pairs. Fertile spikelets sessile; 1 in the cluster. Companion sterile spikelets pedicelled; 1 in the cluster. Pedicels cuneate; 2–2.5 mm long; ciliate; with 0.5–1 mm long hairs.

STERILE SPIKELETS Companion sterile spikelets well-developed; male; lanceolate, or elliptic; dorsally compressed; 5.5–6 mm long; longer than fertile. Companion sterile spikelet glumes chartaceous; glabrous; ciliate on margins; acute; awned; one glume awned; with 5–18 mm long awn. Companion sterile spikelet lemmas 1–2; enclosed by glumes.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets linear; laterally compressed; 4–5 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus 1 mm long; pubescent; base acute; inserted.

GLUMES Glumes dissimilar; exceeding apex of florets; firmer than fertile lemma. Lower glume linear; 1 length of spikelet; coriaceous; 2-keeled; keeled dorsally. Lower glume intercarinal veins absent. Lower glume surface deeply depressed. Lower glume apex dentate; 2 -fid. Upper glume linear; membranous; 1-keeled; 3 -veined. Upper glume awned; 1 -awned. Upper glume awn 10–15 mm long.

FLORETS Basal sterile florets barren; without significant palea. Lemma of lower sterile floret oblong; 3–4.2 mm long; hyaline; 2 -veined; ciliate on margins. Fertile lemma lanceolate; 2.8–4 mm long; hyaline; without keel; 1 -veined. Lemma apex lobed; 2 -fid; awned; 1 -awned. Principal lemma awn from a sinus; geniculate; 30–50 mm long overall; with twisted column. Column of lemma awn glabrous. Palea 1.5–2 mm long; 0 -veined.

FLOWER Anthers 3; 1.7–2.1 mm long.

DISTRIBUTION North America: Mexico. South America: Mesoamericana, Caribbean, northern South America, western South America, and Brazil.

NOTES Andropogoneae. Fl Costaric 1993.

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