Rhytachne subgibbosa

HABIT Perennial; caespitose. Culms (30–)90–120 cm long. Ligule a ciliolate membrane. Leaf-blades filiform; convolute; 15–30 cm long; 1–2 mm wide.

INFLORESCENCE Inflorescence composed of racemes.

Racemes 1; single; smoothly terete; 16–30 cm long. Rhachis fragile at the nodes; semiterete; glabrous on surface; glabrous on margins. Spikelet packing with lowest internode elongated (10–20mm, sometimes bearing a triad). Rhachis internodes clavate; 6–11 mm long. Rhachis internode tip transverse; crateriform; with simple rim.

Spikelets in pairs. Fertile spikelets sessile; 1 in the cluster. Companion sterile spikelets pedicelled; 1 in the cluster. Pedicels linear; foliaceous; curved; 2–4 mm long; glabrous.

STERILE SPIKELETS Companion sterile spikelets represented by barren pedicels, or rudimentary, or well-developed; 0–6.5 mm long; deciduous with the fertile. Companion sterile spikelet glumes coriaceous; muticous.

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets ovate; dorsally compressed; 5–9 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus glabrous; base truncate; with central peg; attached transversely.

GLUMES Glumes dissimilar; exceeding apex of florets; firmer than fertile lemma. Lower glume oblong; 1 length of spikelet; coriaceous; without keels. Lower glume surface smooth, or rugose, or muricate. Lower glume apex acute; muticous. Upper glume oblong; membranous; 3 -veined. Upper glume muticous.

FLORETS Basal sterile florets male; with palea. Lemma of lower sterile floret lanceolate; hyaline; acute. Fertile lemma lanceolate; hyaline; without keel. Lemma apex acute.

FLOWER Anthers 3.

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

NOTES Andropogoneae. Gr Bahia.

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