GrassBase - The Online World Grass Flora


W.D. Clayton, M. Vorontsova, K.T. Harman & H. Williamson

© Copyright The Board of Trustees, Royal Botanic Gardens, Kew.

Chondrosum trifidum

HABIT Perennial; caespitose. Rhizomes absent, or short. Culms geniculately ascending; slender; (8–)10–30(–40) cm long; wiry. Leaves mostly basal. Ligule a fringe of hairs. Leaf-blades 4–8 cm long; 1–1.5 mm wide. Leaf-blade surface smooth, or scaberulous; glabrous, or puberulous.

INFLORESCENCE Inflorescence composed of racemes.

Racemes 2–7; borne along a central axis; unilateral; 1.2–2.5 cm long; bearing 8–24(–32) fertile spikelets on each. Central inflorescence axis 3–9 cm long. Rhachis semiterete; terminating in a barren extension; extension subulate. Spikelet packing broadside to rhachis; crowded.

Spikelets pectinate; solitary. Fertile spikelets sessile.

FERTILE SPIKELETS Spikelets comprising 1 fertile florets; with diminished florets at the apex. Spikelets cuneate; laterally compressed; 4–5 mm long; breaking up at maturity; disarticulating below each fertile floret.

GLUMES Glumes persistent; similar; exceeding apex of florets; thinner than fertile lemma; gaping. Lower glume lanceolate; 3–4 mm long; 0.75 length of upper glume; membranous; 1-keeled; 1 -veined. Lower glume lateral veins absent. Lower glume apex acute to setaceously attenuate. Upper glume lanceolate; 4–5 mm long; 2–2.5 length of adjacent fertile lemma; membranous; 1-keeled; 1 -veined. Upper glume lateral veins absent. Upper glume apex acute to setaceously attenuate.

FLORETS Fertile lemma oblong; 2 mm long; coriaceous; keeled; 3 -veined. Lemma surface glabrous, or pubescent; hairy at base. Lemma hairs 0.2–0.5 mm long. Lemma apex lobed; 3 -fid; awned; 3 -awned. Principal lemma awn 3–4 mm long overall. Lateral lemma awns arising on margin of lemma; 3–4 mm long; subequal to principal. Palea 2 -veined. Rhachilla extension glabrous. Apical sterile florets 1 in number; barren; rudimentary. Apical sterile lemmas awned; 3 -awned. Apical sterile lemma awns 3.5–6 mm long.

FRUIT Caryopsis with adherent pericarp; ellipsoid; 1 mm long. Embryo 0.66 length of caryopsis.

DISTRIBUTION North America: southwest USA, south-central USA, and Mexico.

NOTES Cynodonteae. Gould.

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