Hyparrhenia rufa

HABIT Perennial; caespitose. Rhizomes short. Butt sheaths glabrous. Basal innovations intravaginal. Culms erect; 30–250 cm long; 2–6 mm diam. Culm-internodes solid. Lateral branches fastigiate. Leaves cauline. Leaf-sheaths wider than blade at the collar. Ligule an eciliate membrane; 2–3 mm long. Leaf-blades 30–60 cm long; 2–8 mm wide. Leaf-blade margins smooth. Leaf-blade apex attenuate; filiform.

INFLORESCENCE Synflorescence compound; paniculate to fasciculate; 5–80 cm long. Inflorescence composed of racemes; terminal and axillary; subtended by a spatheole; exserted. Spatheole linear to lanceolate; 3–5 cm long; membranous. Peduncle 3–8 cm long; glabrous, or pilose above.

Racemes 2; paired; erect; unilateral; 2–2.5 cm long; bearing few fertile spikelets; bearing 4–7 fertile spikelets on each. Rhachis fragile at the nodes; ciliate on margins. Rhachis hairs red. Rhachis internodes linear. Rhachis internode tip oblique; flat. Raceme-bases filiform; unequal (the longer measured); 2–3.5 mm long; glabrous.

Spikelets appressed; in pairs. Fertile spikelets sessile; 1 in the cluster. Companion sterile spikelets pedicelled; 1 in the cluster. Pedicels linear; flattened; ciliate; tip oblique.

STERILE SPIKELETS Basal sterile spikelets well-developed; 2 in number (lower raceme); 0–2 in upper raceme; equalling fertile. Basal sterile spikelet glumes smooth on margins; lower glume muticous.

Companion sterile spikelets well-developed; containing empty lemmas, or male; lanceolate; dorsally compressed; 3.5–5 mm long; as long as fertile; separately deciduous. Companion sterile spikelet glumes chartaceous; pilose; with white hairs (rarely), or red hairs; acute; muticous. Companion sterile spikelet lemmas 2; enclosed by glumes.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate; dorsally compressed; 3.5–4.5 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus oblong to cuneate; 0.2–0.8 mm long; pubescent; base obtuse; attached obliquely. Spikelet callus hairs white, or yellow.

GLUMES Glumes dissimilar; with lower wider than upper; exceeding apex of florets; firmer than fertile lemma; shiny. Lower glume lanceolate; 1 length of spikelet; coriaceous; without keels; 5 -veined. Lower glume surface pilose. Lower glume hairs red. Lower glume apex dentate; 2 -fid. Upper glume linear; 1.1 length of adjacent fertile lemma; coriaceous; without keels; 3 -veined. Upper glume apex dentate; 2 -fid; mucronate.

FLORETS Basal sterile florets barren; without significant palea. Lemma of lower sterile floret lanceolate; 1 length of fertile lemma; hyaline; 2 -veined; entire. Fertile lemma linear; 3–4 mm long; membranous; without keel; 1 -veined. Lemma apex dentate; 2 -fid; awned; 1 -awned. Principal lemma awn from a sinus; geniculate; 20–30 mm long overall; with twisted column. Column of lemma awn pubescent (rufously). Palea absent or minute.

FLOWER Lodicules 2; cuneate; fleshy. Anthers 3; 1 mm long. Stigmas 2.

DISTRIBUTION Africa: Macaronesia, west tropical, west-central tropical, northeast tropical, east tropical, southern tropical, south, and western Indian ocean. Asia-temperate: China. Asia-tropical: India, Indo-China, Malesia, and Papuasia. Australasia: Australia. Pacific: southwestern, south-central, northwestern, and north-central. North America: southeast USA and Mexico. South America: Mesoamericana, Caribbean, northern South America, western South America, Brazil, and southern South America.

NOTES Andropogoneae. WDC.

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