Andropogon ternatus

HABIT Perennial; caespitose. Basal innovations intravaginal. Culms erect; 20–70 cm long; 3–4 -noded. Culm-nodes glabrous. Lateral branches sparse. Leaves mostly basal. Leaf-sheaths 2–9 cm long; glabrous on surface, or puberulous. Ligule a ciliolate membrane; 0.4–0.6 mm long; truncate. Leaf-blades 4.5–30 cm long; 2–3.5 mm wide. Leaf-blade surface glabrous, or pubescent; hairy adaxially. Leaf-blade margins scabrous.

INFLORESCENCE Inflorescence composed of racemes.

Racemes 2–4; paired, or digitate; 2.5–7 cm long. Rhachis fragile at the nodes; villous on margins. Rhachis hairs 7–8 mm long. Rhachis internodes linear; 0.66 length of fertile spikelet. Rhachis internode tip transverse; cupuliform; with simple rim.

Spikelets ascending; in pairs. Fertile spikelets sessile; 1 in the cluster. Companion sterile spikelets pedicelled; 1 in the cluster. Pedicels linear; 0.75 length of fertile spikelet; villous; with 7–8 mm long hairs.

STERILE SPIKELETS Companion sterile spikelets represented by single glumes; lanceolate; 2.4–5 mm long; shorter than fertile; separately deciduous. Companion sterile spikelet glumes chartaceous; glabrous; acute; muticous.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate; dorsally compressed; 5–6.6 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus pilose; 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 dorsally. Lower glume surface concave. Upper glume linear; coriaceous; 1-keeled. Upper glume muticous, or awned; 1 -awned. Upper glume awn 0.8–3 mm long.

FLORETS Basal sterile florets barren; without significant palea. Lemma of lower sterile floret oblong; 3.8 mm long; hyaline; 2 -veined; ciliate on margins. Fertile lemma lanceolate; 3–4.6 mm long; hyaline; without keel; 1 -veined. Lemma margins ciliate. Lemma apex lobed; 2 -fid; incised 0.33 of lemma length; awned; 1 -awned. Principal lemma awn from a sinus; geniculate; 13–22 mm long overall; with twisted column. Column of lemma awn 3.5–7 mm long; glabrous.

FLOWER Anthers 3; 1.5–2.3 mm long.

FRUIT Caryopsis 2–3 mm long; dark brown.

DISTRIBUTION South America: Caribbean, northern South America, western South America, Brazil, and southern South America.

NOTES Andropogoneae. Herve & Valls 1995.

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