Andropogon tracyi

HABIT Perennial; caespitose. Culms 50–80 cm long. Lateral branches sparse. Leaf-sheaths keeled; smooth; glabrous on surface. Ligule an eciliate membrane. Leaf-blades 10–20 cm long; 1–3 mm wide. Leaf-blade surface scabrous; rough adaxially. Leaf-blade apex abruptly acute.

INFLORESCENCE Synflorescence compound; linear. Inflorescence composed of racemes; terminal and axillary; subtended by a spatheole; embraced at base by subtending leaf, or enclosed. Spatheole lanceolate; 4–5 cm long. Peduncle 1–3 cm long.

Racemes 2; paired; 3–4 cm long. Rhachis fragile at the nodes; plumose on margins. Rhachis hairs 6 mm long. Rhachis internodes linear; 2–2.5 mm long. Rhachis internode tip transverse; cupuliform; with simple rim.

Spikelets ascending, or spreading; in pairs. Fertile spikelets sessile; 1 in the cluster. Companion sterile spikelets pedicelled; 1 in the cluster. Pedicels filiform; 5–6 mm long; plumose; with 6 mm long hairs.

STERILE SPIKELETS Companion sterile spikelets represented by barren pedicels, or represented by single glumes; linear; 0–1 mm long; shorter than fertile. Companion sterile spikelet glumes chartaceous; muticous.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate; dorsally compressed; 4.5–5 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus pubescent; base obtuse; inserted.

GLUMES Glumes dissimilar; exceeding apex of florets; firmer than fertile lemma. Lower glume lanceolate; 1 length of spikelet; cartilaginous; 2-keeled; keeled dorsally. Lower glume primary vein ciliolate. Lower glume intercarinal veins absent. Lower glume surface concave. Upper glume lanceolate; membranous; 1-keeled. Upper glume muticous.

FLORETS Basal sterile florets barren; without significant palea. Lemma of lower sterile floret oblong; hyaline. Fertile lemma lanceolate; hyaline; without keel. Lemma apex lobed; 2 -fid; awned; 1 -awned. Principal lemma awn from a sinus; geniculate; 15–20 mm long overall; with twisted column. Column of lemma awn glabrous.

FLOWER Anthers 1.

DISTRIBUTION North America: southeast USA.

NOTES Andropogoneae. N Amer Fl 1994.

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