Andropogon crassus

HABIT Perennial; caespitose. Culms erect; 100–200 cm long. Culm-nodes glabrous. Leaf-sheaths glabrous on surface. Ligule an eciliate membrane; 1.5 mm long. Leaf-blades 20–45 cm long; 10–20 mm wide. Leaf-blade surface glabrous; hairless except near base. Leaf-blade margins scabrous. Leaf-blade apex attenuate.

INFLORESCENCE Synflorescence compound; linear. Inflorescence composed of racemes; terminal and axillary; subtended by a spatheole; enclosed. Spatheole linear.

Racemes 1; single; 1–4 cm long. Rhachis fragile at the nodes; with scattered hairs; ciliate on margins. Rhachis internodes clavate; 3 mm long. Rhachis internode tip transverse; cupuliform; with simple rim.

Spikelets in pairs. Fertile spikelets sessile; 1 in the cluster. Companion sterile spikelets pedicelled; 1 in the cluster. Pedicels linear; 2.5 mm long; ciliate; hairy on margins.

STERILE SPIKELETS Companion sterile spikelets well-developed; comprising 2 subequal glumes without lemmas; linear; 3–4 mm long; as long as fertile; separately deciduous. Companion sterile spikelet glumes chartaceous.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate; dorsally compressed; 4–4.2 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus base obtuse; inserted.

GLUMES Glumes dissimilar; exceeding apex of florets; firmer than fertile lemma. Lower glume lanceolate; 1 length of spikelet; coriaceous; 2-keeled; keeled laterally; 4 -veined. Lower glume surface concave. Upper glume linear; coriaceous; 1-keeled; 3 -veined. Upper glume primary vein scabrous. Upper glume muticous.

FLORETS Basal sterile florets barren; with palea, or without significant palea. Lemma of lower sterile floret oblong; 2.8–4 mm long; hyaline; 3 -veined; ciliolate on margins. Palea of lower sterile floret 0–2 mm long. Fertile lemma lanceolate; 2–3.2 mm long; hyaline; without keel. Lemma apex lobed; 2 -fid; awned; 1 -awned. Principal lemma awn from a sinus; geniculate; 5–8 mm long overall; with a straight or slightly twisted column. Column of lemma awn glabrous. Palea 2–2.5 mm long; hyaline.

FLOWER Lodicules 2; 0.5–0.7 mm long. Anthers 3; 1.5–1.8 mm long.

DISTRIBUTION South America: northern South America.

NOTES Andropogoneae. Sohns 2004.

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