Ctenium planifolium

HABIT Perennial; caespitose. Butt sheaths persistent and investing base of culm; with fibrous dead sheaths. Culms 50–100 cm long. Culm-internodes distally pubescent. Leaf-sheaths smooth, or scaberulous. Ligule an eciliate membrane; 0.5–1 mm long. Leaf-blades flat; 10–20 cm long; 2–4 mm wide. Leaf-blade surface scaberulous. Leaf-blade apex acuminate, or attenuate.

INFLORESCENCE Inflorescence composed of racemes. Peduncle pubescent above.

Racemes 1; single; arcuate; unilateral; 5–10 cm long. Rhachis semiterete; 1.5 mm wide; pubescent on surface; terminating in a barren extension; extension subulate. Spikelet packing broadside to rhachis; crowded; regular; 2 -rowed.

Spikelets pectinate; solitary. Fertile spikelets sessile.

FERTILE SPIKELETS Spikelets comprising 2 basal sterile florets; 1 fertile florets; with diminished florets at the apex. Spikelets cuneate; laterally compressed; 8 mm long; breaking up at maturity; disarticulating below each fertile floret. Floret callus pilose.

GLUMES Glumes persistent; dissimilar; exceeding apex of florets; firmer than fertile lemma; gaping. Lower glume ovate; 2 mm long; 0.25 length of upper glume; membranous; 1-keeled; 1 -veined. Lower glume lateral veins absent. Lower glume apex acute. Upper glume lanceolate; 8 mm long; 1.5 length of adjacent fertile lemma; herbaceous; with hyaline margins; 1-keeled; 3 -veined. Upper glume primary vein tuberculate. Upper glume surface tuberculate; rough on veins; puberulous. Upper glume apex acuminate; awned; 1 -awned. Upper glume awn dorsal and oblique; 2 mm long.

FLORETS Basal sterile florets dissimilar; barren; without significant palea; attached to and deciduous with the fertile. Lemma of lower sterile floret elliptic; 3.5 mm long; membranous; 1-keeled; puberulous; ciliate on margins; fringed all along; obtuse; awned. Awn of lower sterile floret subapical; 4 mm long. Lemma of upper sterile floret elliptic; 4.5 mm long; membranous; pubescent; ciliate on margins; fringed above; obtuse; awned. Awn of upper sterile floret subapical; 5–6 mm long. Fertile lemma ovate; 5–6 mm long; membranous; keeled; 3 -veined. Lemma margins ciliate; hairy above. Lemma hairs 2–3 mm long. Lemma apex awned; 1 -awned. Principal lemma awn subapical; 2–3 mm long overall. Palea 2 -veined. Palea keels scabrous. Palea surface pubescent; hairy on back. Palea apex acute. Apical sterile florets 1–4 in number; separate; lanceolate; 3 mm long. Apical sterile lemmas pilose; adorned on margins; awned; 1 -awned. Apical sterile lemma awns 2 mm long.

FRUIT Caryopsis with adherent pericarp; obovoid; 2 mm long; red.

DISTRIBUTION North America: Mexico.

NOTES Cynodonteae. N Amer Fl 1993.

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