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.

Cenchrus

HABIT Annual (14), or perennial (11). Rhizomes absent (21), or short (3). Culms erect (6/15), or geniculately ascending (12/15), or decumbent (2/15); robust (3/3); 5–60.5–300 cm long; firm (23), or wiry (1). Culm-internodes unequal, the upper longer (1/1); channelled (1/1). Culm-nodes constricted (1/1). Lateral branches sparse (1/2), or ample (1/2). Branch complement one (1/1), or two (1/1); with subequal branches (1/1); thinner than stem (1/1). Leaf-sheaths open for most of their length (2/2). Ligule a ciliate membrane (1), or a fringe of hairs (23). Leaf-blades linear, or lanceolate (1). Leaf-blade midrib conspicuous (1/1). Leaf-blade margins unthickened (1/1). Leaf-blade apex muticous (23), or pungent (1).

INFLORESCENCE Inflorescence a panicle.

Panicle spiciform. Panicle axis bearing deciduous spikelet clusters.

Spikelets subtended by an involucre. Fertile spikelets sessile; 1 in the cluster (14), or 2 in the cluster (19), or 3 in the cluster (16), or 4 in the cluster (4), or 5–8 in the cluster (1). Involucre composed of bristles; connate into a disc below (8), or connate into a cup below (16). Involucral bristles deciduous with the fertile spikelets; few (12), or numerous (12); 5–28–75 in principal whorl; terete (5), or flattened (18), or expanded (1); flexible (5), or rigid (19); obtuse (2), or spinose (16), or attenuate (8).

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate (6), or ovate (20); dorsally compressed; 2–5.294–9 mm long; falling entire; deciduous with accessory branch structures.

GLUMES Glumes one the lower absent or obscure (4), or two (22); shorter than spikelet (23), or reaching apex of florets (1); thinner than fertile lemma. Lower glume lanceolate (4/22), or ovate (20/22); hyaline (4/22), or membranous (19/22); without keels (22/22); 0 -veined (3/22), or 1 -veined (22/22), or 2–3 -veined (1/22). Lower glume lateral veins absent (21/22), or distinct (1/22). Lower glume surface without pits (22/22); glabrous (20/22), or puberulous (2/22). Lower glume apex obtuse (8/22), or acute (19/22), or acuminate (1/22). Upper glume lanceolate (1), or oblong (1), or ovate; hyaline (2), or membranous (22); without keels; 1 -veined (8), or 2 -veined (6), or 3 -veined (19), or 4 -veined (13), or 5 -veined (16), or 6–7 -veined (2). Upper glume surface smooth (23), or asperulous (1); glabrous (20), or puberulous (4). Upper glume apex obtuse (6/23), or acute (22/23), or acuminate (1/23), or setaceously attenuate (1/23).

FLORETS Basal sterile florets male (5), or barren (21); with palea (22), or without significant palea (4). Lemma of lower sterile floret lanceolate (2), or oblong (3), or ovate (20); 1 length of fertile lemma; membranous; 3 -veined (9), or 4 -veined (7), or 5 -veined (22), or 6–7 -veined (8); emarginate (1), or obtuse (2), or acute (21), or acuminate (2); muticous (22), or mucronate (3). Fertile lemma lanceolate (2), or elliptic (1), or ovate (21); dorsally compressed (4/4); lanceolate in profile (1/1); chartaceous (3), or cartilaginous (1), or coriaceous (22); of similar consistency on margins (4), or much thinner on margins (20); without keel; wingless; 3 -veined (12/23), or 4 -veined (2/23), or 5 -veined (13/23), or 6–7 -veined (1/23). Lemma surface smooth (22), or granulose (1), or asperulous (1); unwrinkled; without grooves. Lemma margins exposing palea (20), or covering most of palea (4). Lemma apex truncate (1), or obtuse (14), or acute (8), or acuminate (4); without ornament (23), or pubescent (1); muticous (20), or mucronate (4). Palea 1 length of lemma; chartaceous (3), or cartilaginous (1), or coriaceous (22); 2 -veined (4/4).

FLOWER Lodicules absent (3/4), or 2 (1/4); fleshy (1/1). Anthers 3 (11/11). Stigmas 2 (1/1). Ovary glabrous (1/1).

FRUIT Caryopsis with adherent pericarp (21/21); ellipsoid (3/11), or oblong (2/11), or ovoid (4/11), or orbicular (1/11), or obovoid (2/11); dorsally compressed (8/8); apex unappendaged (1/1).

DISTRIBUTION Europe (2), or Africa (11), or Temperate Asia (8), or Tropical Asia (9), or Australasia (11), or Pacific (7), or North America (11), or South America (13).

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