Andropogon leucostachyus

HABIT Perennial; caespitose. Culms erect; 40–110 cm long; 0.7–2 mm diam. Culm-internodes solid. Culm-nodes glabrous. Lateral branches sparse. Leaves mostly basal. Leaf-sheaths keeled; glabrous on surface. Ligule a ciliolate membrane; 0.7–1.7 mm long. Leaf-blades flat, or conduplicate; 15–32 cm long; 1.5–2.5 mm wide. Leaf-blade apex acuminate.

INFLORESCENCE Synflorescence compound; scanty. Inflorescence composed of racemes; terminal and axillary; subtended by a spatheole. Spatheole linear; 4–6 cm long.

Racemes 2–4; paired, or digitate; 2–5.5 cm long. Rhachis fragile at the nodes; plumose on surface; plumose on margins. Rhachis hairs lengthening towards internode tip; 5–10 mm long. Rhachis internodes linear; 1.8–2.7 mm long. 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; 2.5–3.5 mm long; plumose; with 5–10 mm long hairs.

STERILE SPIKELETS Companion sterile spikelets represented by single glumes; linear; 1.1–1.5 mm long; shorter than fertile. 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; 2–3.5 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus bearded; base obtuse; inserted. Spikelet callus hairs 4–5 mm long.

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

FLORETS Basal sterile florets barren; without significant palea. Lemma of lower sterile floret oblong; 1.8–2.6 mm long; hyaline; 2 -veined; ciliate on margins; fringed above. Fertile lemma lanceolate; 1.5–2.5 mm long; hyaline; without keel. Lemma apex entire; acuminate; muticous, or mucronate. Palea absent or minute.

FLOWER Anthers 3.

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

NOTES Andropogoneae. Fl Costaric 1993.

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