Andropogon vetus

HABIT Perennial; caespitose. Culms erect; 100–400 cm long. Culm-internodes distally glabrous. Leaf-sheaths longer than adjacent culm internode; glabrous on surface. Leaf-sheath auricles erect. Ligule an eciliate membrane; 3–5 mm long. Leaf-blade base tapering to the midrib. Leaf-blades 30–60 cm long; 10–15 mm wide. Leaf-blade surface glabrous. Leaf-blade apex attenuate.

INFLORESCENCE Synflorescence compound; linear. Inflorescence composed of racemes; terminal and axillary; subtended by a spatheole; embraced at base by subtending leaf. Spatheole linear.

Racemes 1; single; 1–3 cm long. Rhachis fragile at the nodes; villous on margins. Rhachis hairs 1–3 mm long. Rhachis internodes clavate; 2–3.5 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; 3.5–3.8 mm long; villous; hairy on margins.

STERILE SPIKELETS Companion sterile spikelets well-developed; comprising 2 subequal glumes without lemmas, or containing empty lemmas; lanceolate; 2.4–3.4 mm long; shorter than fertile; separately deciduous. Companion sterile spikelet glumes chartaceous. Companion sterile spikelet lemmas enclosed by glumes.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate; dorsally compressed; 3.7–5.3 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; 6 -veined. Lower glume primary vein scaberulous. Lower glume surface flat; glabrous. Upper glume linear; coriaceous; 1-keeled. Upper glume muticous.

FLORETS Basal sterile florets barren; without significant palea. Lemma of lower sterile floret oblong; hyaline; 2-keeled. Fertile lemma lanceolate; 3–4 mm long; hyaline; without keel. Lemma apex lobed; 2 -fid; with lobes 1 mm long; awned; 1 -awned. Principal lemma awn from a sinus; geniculate; 10–25 mm long overall; with twisted column. Column of lemma awn glabrous. Palea 1.5–2 mm long; hyaline; 2-keeled. Palea keels ciliolate.

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

DISTRIBUTION South America: northern South America and western South America.

NOTES Andropogoneae. Sohns 2004.

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