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GrassBase - The Online World Grass Flora
Descriptions
W.D. Clayton, M. Vorontsova, K.T. Harman & H. Williamson
© Copyright The Board of Trustees, Royal Botanic Gardens, Kew.
Ctenium plumosum
HABIT Perennial; caespitose. Culms erect; 70–80 cm long. Culm-internodes distally pubescent. Leaf-sheaths scaberulous. Ligule an eciliate membrane; 1 mm long; truncate. Leaf-blades involute; 10–25 cm long; 1–2 mm wide. Leaf-blade surface scabrous. Leaf-blade apex attenuate.
INFLORESCENCE Inflorescence composed of racemes. Peduncle pubescent above.
Racemes 1–3; single, or digitate; flexuous; unilateral; 5–10 cm long. Rhachis semiterete; 1 mm wide; scabrous on surface; glabrous on surface; ciliate on margins; 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; 5 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; 0.4 length of upper glume; membranous; 1-keeled; 1 -veined. Lower glume lateral veins absent. Lower glume apex acute. Upper glume ovate; 5 mm long; 1.6 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. Upper glume apex acute; awned; 1 -awned. Upper glume awn dorsal and oblique; 4 mm long; plumose.
FLORETS Basal sterile florets dissimilar; barren; without significant palea; attached to and deciduous with the fertile. Lemma of lower sterile floret elliptic; 1.5–2 mm long; membranous; 1-keeled; ciliate on margins; fringed all along; dentate; 2 -fid; acute; awned. Awn of lower sterile floret 4 mm long. Lemma of upper sterile floret elliptic; 3 mm long; membranous; ciliate on margins; fringed above; acute; awned. Awn of upper sterile floret subapical; 8–10 mm long. Fertile lemma ovate; 3 mm long; membranous; keeled; 3 -veined. Lemma margins ciliate; hairy above. Lemma apex awned; 1 -awned. Principal lemma awn subapical; 8–10 mm long overall. Palea 1 length of lemma; 2 -veined. Apical sterile florets 2 in number; separate; elliptic; 2 mm long.
FRUIT Caryopsis with adherent pericarp.
DISTRIBUTION North America: Mexico.
NOTES Cynodonteae. N Amer Fl 1993.
Please cite this publication as detailed in How to Cite Version: 3rd February 2016.
