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.

Chondrosum

HABIT Annual (4), or perennial (14). Rhizomes absent (14), or short (3). Stolons absent, or present (3). Culms erect (8), or geniculately ascending (8), or decumbent (5); slender (5/5); 3–39.4–140 cm long; firm (13), or wiry (4); without nodal roots (1/1), or rooting from lower nodes (1/1). Culm-nodes swollen (1/1). Lateral branches lacking (2/3), or ample (1/3). Ligule a ciliolate membrane (1), or a ciliate membrane (1), or a fringe of hairs (14).

INFLORESCENCE Inflorescence composed of racemes. Peduncle tipped by a glumaceous appendage (1/1).

Racemes single (6), or borne along a central axis (14); erect (3), or ascending (13), or spreading (2); linear, or oblong (2); unilateral; bearing 7–35–100 fertile spikelets on each. Central inflorescence axis tip without extension (14/14), or subulate (2/14). Rhachis flattened (3/15), or semiterete (12/15); terminating in a spikelet (10), or sterile spikelet (2), or barren extension (5); extension subulate (3/5), or bristle-like (2/5). Spikelet packing broadside to rhachis; crowded (13), or contiguous (2), or lax (1).

Spikelets ascending (2), or pectinate (14); solitary. Fertile spikelets sessile (15), or pedicelled (1). Pedicels linear (1/1).

FERTILE SPIKELETS Spikelets comprising 1 fertile florets; with diminished florets at the apex. Spikelets cuneate; laterally compressed; 2.5–4.677–9 mm long; breaking up at maturity; disarticulating below each fertile floret. Floret callus brief (15), or evident (1); pilose (6/6).

GLUMES Glumes persistent; shorter than spikelet (4), or reaching apex of florets (8), or exceeding apex of florets (4); thinner than fertile lemma; parallel to lemmas (2), or gaping (14). Lower glume lanceolate; 0.33–0.6641–1 length of upper glume; membranous; 1-keeled; 1 -veined. Lower glume lateral veins absent (15), or distinct (1). Lower glume surface smooth (15), or asperulous (1); without pits; glabrous (15), or puberulous (1), or pubescent (1). Lower glume apex entire (14), or dentate (3); 2 -fid (3/3); obtuse (1), or acute (5), or acuminate (12), or attenuate (2), or setaceously attenuate (2); muticous (11), or mucronate (5), or awned (1). Upper glume lanceolate; 0.66–1.091–2.5 length of adjacent fertile lemma; membranous; 1-keeled; 1 -veined. Upper glume primary vein eciliate (14), or ciliate (3). Upper glume surface smooth (15), or asperulous (1), or scabrous (1); glabrous (12), or puberulous (2), or pubescent (1), or pilose (1), or villous (1), or woolly (1); with simple hairs (4/5), or tubercle-based hairs (1/5). Upper glume apex entire (13), or dentate (4); 2 -fid (4/4); obtuse (1), or acute (5), or acuminate (12), or attenuate (2), or setaceously attenuate (2); muticous (10), or mucronate (4), or awned (3); 1 -awned (3/3).

FLORETS Fertile lemma oblong (15), or ovate (1); coriaceous; keeled; wingless; 3 -veined. Lemma midvein eciliate (14), or ciliate (1), or pubescent (1). Lemma lateral veins excurrent (1/1). Lemma surface unwrinkled; without grooves; glabrous (6), or puberulous (1), or pubescent (11), or pilose (2), or woolly (1). Lemma margins eciliate (13), or ciliate (1), or pubescent (2). Lemma apex entire (1), or dentate (1), or lobed (14); 2 -fid (1/15), or 3 -fid (14/15); incised 0.3 of lemma length; muticous (1), or mucronate (1), or awned (14); 1 -awned (3/14), or 3 -awned (11/14). Principal lemma awn apical (12/15), or from a sinus (3/15). Lateral lemma awns longer than principal (1/11), or subequal to principal (7/11), or shorter than principal (3/11). Palea 2 -veined. Palea keels eciliate (15), or ciliolate (1). Palea surface glabrous (14), or pubescent (2). Palea apex dentate (2/2); muticous (13), or with excurrent keel veins (1), or awned (2). Apical sterile florets 1 in number (12), or 2 in number (8); barren; separate (11), or in a clump (5); rudimentary (5), or oblong (1), or cuneate (10). Apical sterile lemmas awned.

FLOWER Anthers 3 (2/2).

FRUIT Caryopsis with adherent pericarp; ellipsoid (2/12), or oblong (1/12), or obovoid (9/12); trigonous (1/1). Embryo 0.66–0.7367–0.9 length of caryopsis.

DISTRIBUTION North America, or South America (3).

Please cite this publication as detailed in How to Cite Version: 27th January 2014.