Cenchrus L.

M. Thulin et al. Flora of Somalia, Vol. 1-4 [updated 2008] https://plants.jstor.org/collection/FLOS

Morphology General Habit

Annual or perennial; leaves flat or inrolled; ligule a line of hairs

Morphology Reproductive morphology Inflorescences

Inflorescence a cylindrical spike-like panicle with angular rhachis, each spikelet or cluster of spikelets enclosed by a deciduous involucre; involucre composed of 1 or more whorls of bristles, those of the innermost whorl ± flattened and often spiny, connate at the base or for some distance along their length

Morphology Reproductive morphology Inflorescences Spikelets

Spikelets lanceolate to ovate, dorsally compressed, acute to acuminate; lower glume up to 1/2 the length of the spikelet, sometimes suppressed; upper glume a little shorter than the spikelet; lower floret male or barren, its lemma as long as the spikelet, membranous; upper lemma as long as the spikelet, firmly membranous to coriaceous, its thin flat margins covering much of the palea

Morphology Reproductive morphology Fruits

Caryopsis elliptic to ovoid, dorsally compressed.

Distribution

Over 100 species throughout the tropics.

Gramineae, W. D. Clayton, S. M. Phillips And S. A. Renvoize. Flora of Tropical East Africa. 1974

Morphology General Habit

Annuals or perennials

Morphology Leaves

Leaf-blades flat or involute; ligule a line of hairs

Morphology Reproductive morphology Inflorescences

Inflorescence a cylindrical spike-like panicle with angular rhachis, each spikelet or cluster of spikelets enclosed by a deciduous involucre; involucre composed of 1 or more whorls of bristles, those of the innermost whorl ± flattened and often spiny, connate at the base or for some distance along their length

Morphology Reproductive morphology Inflorescences Spikelets

Spikelets lanceolate to ovate, dorsally compressed, acute to acuminate; lower glume up to 1/2 as long as the spikelet, sometimes suppressed; upper glume a little shorter than the spikelet; lower floret ♂ or barren, its lemma as long as the spikelet, membranous; upper lemma as long as the spikelet, firmly membranous to coriaceous, the flat thin margins covering much of the palea

Morphology Reproductive morphology Fruits

Caryopsis elliptic to ovoid, dorsally compressed.

Gramineae, W. D. Clayton. Flora Zambesiaca 10:3. 1989

Morphology Reproductive morphology Inflorescences

Inflorescence a cylindrical spiciform panicle with angular rhachis, bearing deciduous clusters of 1-several spikelets subtended by an involucre of bristles, these flexuous or spinous, ± flattened and united below (at least the inner whorl), the degree of union varying from a basal disk to a deep cupule.

Morphology Reproductive morphology Inflorescences Spikelets

Spikelets lanceolate to ovate.

Morphology Reproductive morphology Inflorescences Bracts Glume

Inferior glume up to 1/2 length of spikelet, sometimes suppressed. Superior glume and inferior lemma as long as spikelet or a little shorter.

Morphology Reproductive morphology Inflorescences Bracts Lemma

Superior lemma chartaceous to thinly coriaceous with flat thin margins.

George R. Proctor (2012). Flora of the Cayman Isands (Second Edition). Royal Botanic Gardens, Kew

Morphology General Habit

Annuals or perennials, with terminal racemes of spiny burs

Morphology Reproductive morphology Inflorescences Spikelets

Spikelets sessile, 1 to several together, permanently enclosed in a bristly or spiny involucre or bur, composed of more or less coalesced sterile branchlets; burs sessile or nearly so on a slender, compressed or angled axis, its apex produced into a short point beyond the uppermost bur, the burs falling entire, the grains germinating within them; involucre somewhat oblique, its body irregularly cleft, the lobes rigid, in most species resembling the spines, the cleft on the side of the bur next to the axis reaching to the tapering, abruptly narrowed or truncate base, the bristles or spines barbed, at least toward the summit; spikelets mostly glabrous or nearly so; first glume 1-nerved, usually narrow, sometimes lacking; second glume and sterile lemma 3–5-nerved, the lemma enclosing a well developed palea and usually a staminate flower

Morphology Reproductive morphology Fruits

Fruit usually turgid, indurate, the lemma acuminate, the nerves visible toward the summit, the margins thin, flat.

Distribution

About 25 tropical and warm-temperate species.

Note

Most are troublesome weeds because of their prickly burs.

George R. Proctor (2012). Flora of the Cayman Isands (Second Edition). Royal Botanic Gardens, Kew

Morphology General Habit

Annuals or perennials, with usually flat leaf-blades and dense spike-like panicles

Morphology Reproductive morphology Inflorescences Spikelets

Spikelets solitary or in groups of 2 or 3, surrounded by an involucre of bristles, these not united except at the very base, often plumose, falling attached to the spikelets; first glume shorter than the spikelet, sometimes minute or lacking; second glume shorter than or equal in length to the sterile lemma; fertile lemma chartaceous, smooth, the margin thin, enclosing the palea.

Distribution

A genus of 130 species widely distributed in warm regions (chiefly Old World).

Gramineae, W. D. Clayton. Flora Zambesiaca 10:3. 1989

Morphology Reproductive morphology Inflorescences

Inflorescence a cylindrical to subglobose spiciform panicle, terminal or sometimes axillary and then often aggregated into a leafy false panicle, bearing deciduous clusters of 1-several spikelets subtended by an involucre of bristles, these flexuous, filiform and free to the base.

Morphology Reproductive morphology Inflorescences Spikelets

Spikelets narrowly lanceolate to oblong.

Morphology Reproductive morphology Inflorescences Bracts Glume

Glumes and inferior lemma variable, absent to as long as spikelet.

Morphology Reproductive morphology Inflorescences Bracts Lemma

Superior lemma cartilaginous to thinly coriaceous with flat thin margins.

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Morphology General Habit

Annual (12), or perennial (71). Rhizomes absent (55), or short (11), or elongated (17). Stolons absent (79), or present (3). Culms erect (42/63), or geniculately ascending (27/63), or decumbent (13/63), or prostrate (1/63), or rambling (2/63); reed-like (1/17), or robust (10/17), or slender (6/17); 3-130.9-800 cm long; compressible (1), or firm (70), or wiry (7), or woody (6); without nodal roots (3/10), or with prop roots (1/10), or rooting from lower nodes (9/10). Culm-internodes channelled (1/1). Culm-nodes constricted (1/2), or swollen (1/2). Lateral branches lacking (6/40), or sparse (2/40), or ample (26/40), or fastigiate (4/40), or suffrutescent (3/40). Leaf-sheath auricles absent (81), or erect (1). Ligule an eciliate membrane (3), or a ciliolate membrane (3), or a ciliate membrane (14), or a fringe of hairs (62). Leaf-blade base without a false petiole (79), or with a false petiole (5). Leaf-blades persistent (80), or deciduous at the ligule (2); aciculate (1), or filiform (3), or linear (72), or lanceolate (11); membranous (1), or herbaceous (79), or coriaceous (2); stiff (4), or firm (74), or flaccid (4). Leaf-blade midrib widened (1/1). Leaf-blade surface with rectangular ribs (1/1). Leaf-blade margins cartilaginous (2/2). Leaf-blade apex muticous (81), or pungent (1).

Morphology Reproductive morphology Inflorescences

Synflorescence simple (72), or compound (10); scanty (7/9), or paniculate (1/9), or fastigiate (1/9). Inflorescence a panicle (81), or comprising only a few spikelets (1); terminal (58), or terminal and axillary (24); subtended by an unspecialized leaf-sheath (78), or an inflated leaf-sheath (4); exserted (78), or embraced at base by subtending leaf (3), or enclosed (1). Panicle spiciform (81/81). Panicle axis bearing persistent branches (10/81), or deciduous spikelet clusters (71/81). Spikelets solitary (1), or subtended by an involucre. Fertile spikelets sessile (72/81), or sessile and pedicelled (5/81), or pedicelled (5/81); 1 in the cluster (79/81), or 2 in the cluster (18/81), or 3 in the cluster (10/81), or 4 in the cluster (5/81), or 5 in the cluster (3/81), or 6-9 in the cluster (1/81). Companion sterile spikelets sessile (1/5), or pedicelled (4/5); 0-1 in the cluster (1/5), or 2-3 in the cluster (4/5), or 4 in the cluster (3/5), or 5 in the cluster (1/5). Involucre composed of bristles; free throughout (81), or connate into a disc below (1). Involucral bristles persistent (1), or deciduous with the fertile spikelets (81); few (24), or numerous (58); 1-13-80 in principal whorl; terete (81), or flattened (1); flexible (80), or rigid (2).

Sterile

Companion sterile spikelets absent (77), or well-developed (5); deciduous with the fertile (4/4).

Morphology Reproductive morphology Inflorescences Spikelets

Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension, or with a barren rhachilla extension (3). Spikelets lanceolate (59), or elliptic (6), or oblong (12), or ovate (10), or obovate (2); subterete (1), or dorsally compressed (81); 2-5.375-20 mm long; persistent on plant (1), or falling entire (81); deciduous from the base (1/81), or with accessory branch structures (81/81). Spikelet callus pubescent (1/1); base truncate (7/7). Companion sterile spikelets absent (77), or well-developed (5); deciduous with the fertile (4/4).

Fertile

Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension, or with a barren rhachilla extension (3). Spikelets lanceolate (59), or elliptic (6), or oblong (12), or ovate (10), or obovate (2); subterete (1), or dorsally compressed (81); 2-5.375-20 mm long; persistent on plant (1), or falling entire (81); deciduous from the base (1/81), or with accessory branch structures (81/81). Spikelet callus pubescent (1/1); base truncate (7/7).

Morphology Reproductive morphology Inflorescences Bracts Glume

Glumes both absent or obscure (5), or one the lower absent or obscure (23), or two (70); shorter than spikelet (75), or reaching apex of florets (11); thinner than fertile lemma. Lower glume lanceolate (9/70), or elliptic (4/70), or oblong (14/70), or ovate (35/70), or orbicular (7/70), or oblate (13/70); 0.5-0.775-1 length of upper glume; hyaline (33/68), or membranous (35/68); without keels (67/67); 0 -veined (46/68), or 1 -veined (36/68), or 2 -veined (5/68), or 3 -veined (6/68). Lower glume lateral veins absent (64/70), or obscure (2/70), or distinct (6/70). Lower glume surface smooth (69/70), or asperulous (1/70); glabrous (68/70), or puberulous (1/70), or pubescent (1/70). Lower glume apex entire (69/70), or erose (1/70); emarginate (5/67), or truncate (10/67), or obtuse (40/67), or acute (33/67), or acuminate (3/67); muticous (69/70), or mucronate (1/70). Upper glume lanceolate (12), or elliptic (8), or oblong (17), or ovate (48), or oblate (8); hyaline (19), or membranous (62), or herbaceous (1); without keels; 0-3-11 -veined. Upper glume surface smooth (80), or asperulous (3), or scabrous (1); glabrous (79), or puberulous (2), or pubescent (1). Upper glume apex entire, or dentate (1); 3 -fid (1/1); emarginate (7/81), or truncate (6/81), or obtuse (27/81), or acute (56/81), or acuminate (16/81), or caudate (1/81); muticous (80), or mucronate (5).

Morphology Reproductive morphology Flowers Florets

Basal sterile florets male (47), or barren (68); with palea (49), or without significant palea (49). Lemma of lower sterile floret lanceolate (17), or elliptic (19), or oblong (27), or ovate (26), or oblate (1); hyaline (3), or membranous (63), or chartaceous (16); 0-5-15 -veined; emarginate (3/78), or truncate (1/78), or obtuse (12/78), or acute (42/78), or acuminate (29/78), or setaceously attenuate (3/78), or cuspidate (1/78), or caudate (1/78); muticous (75), or mucronate (8), or awned (1). Fertile lemma lanceolate (38), or elliptic (13), or oblong (9), or ovate (24); membranous (25), or chartaceous (28), or cartilaginous (9), or coriaceous (20); of similar consistency above (81), or much thinner above (1); of similar consistency on margins (80), or much thinner on margins (2); without keel; 3-4 -veined (4/56), or 5 -veined (55/56), or 6-7 -veined (13/56), or 8-9 -veined (3/56), or 10-12 -veined (1/56). Lemma surface smooth (69), or asperulous (2), or scaberulous (14); glabrous (81), or hispidulous (1). Lemma margins flat (81), or involute (1); eciliate (79), or ciliolate (1), or pubescent (2). Lemma apex emarginate (1/80), or truncate (1/80), or obtuse (12/80), or acute (46/80), or acuminate (26/80), or setaceously attenuate (1/80), or apiculate (3/80); muticous (76), or mucronate (7). Palea 0.5-0.9879-1.1 length of lemma; membranous (33), or chartaceous (21), or cartilaginous (8), or coriaceous (20); 2 -veined (3/3), or 3-4 -veined (1/3).

Morphology Reproductive morphology Flowers

Lodicules absent (61/64), or 2 (3/64); truncate (1/1). Anthers 3 (77/77). Stigmas 2 (2/2); plumose (81), or pubescent (1).

Morphology Reproductive morphology Fruits

Caryopsis with adherent pericarp (37/37); lanceolate (1/9), or ellipsoid (3/9), or oblong (5/9), or ovoid (2/9), or obovoid (1/9); isodiametric (1/6), or dorsally compressed (6/6). Embryo 0.5 length of caryopsis.

Distribution

Europe (3), or Africa (47), or Temperate Asia (23), or Tropical Asia (18), or Australasia (12), or Pacific (10), or North America (12), or South America (27), or Antarctica (1).

Gramineae, W. D. Clayton, S. M. Phillips And S. A. Renvoize. Flora of Tropical East Africa. 1974

Morphology General Habit

Annuals or perennials

Morphology Leaves

Leaf-blades linear to lanceolate, flat to convolute; ligule a line of hairs, rarely membranous

Morphology Reproductive morphology Inflorescences

Inflorescence a cylindrical to subglobose spike-like panicle terminal on culms and branches, rarely axillary and then often gathered into a leafy false panicle, each spikelet or cluster of spikelets subtended by a deciduous involucre of 1-many slender bristles free throughout; rhachis rounded or angular with or without short peduncle-stumps, occasionally the involucre shortly stipitate below the insertion of the bristles

Morphology Reproductive morphology Inflorescences Spikelets

Spikelets narrowly lanceolate to oblong, dorsally compressed, glabrous or almost so; lower glume up to half as long as the spikelet, sometimes suppressed; upper glume varying from very small to as long as the spikelet; lower floret ♂ or barren, its lemma of variable length, membranous; upper lemma as long as the spikelet or a little shorter, membranous to coriaceous, its flat thin margins covering ± half the palea; anther-tips smooth, or sometimes with a little tuft of hairs

Morphology Reproductive morphology Fruits

Caryopsis oblong and dorsally compressed to subglobose.

Gramineae, W. D. Clayton, S. M. Phillips And S. A. Renvoize. Flora of Tropical East Africa. 1974

Morphology General Habit

Perennial

Morphology Leaves

Leaf-blades flat, linear; ligule a short membranous rim

Morphology Reproductive morphology Inflorescences

Inflorescence a coarse cylindrical raceme embraced below by the uppermost leaf sheath, each spikelet subtended by a lobed herbaceous scale forming an involucre

Morphology Reproductive morphology Inflorescences Spikelets

Spikelets lanceolate, dorsally compressed; lower glume a minute hyaline scale or absent; upper glume shorter than the spikelet; lower floret ♂, with a palea, as long as the spikelet; upper lemma as long as the spikelet, cartilaginous, its margins covering 2/3 of the palea; stigma 1, long, flexuous

Morphology Reproductive morphology Fruits

Caryopsis oblong, dorsally compressed.

nonem

Morphology General Habit

Perennial. Culms prostrate; 20-40 cm long; spongy; rooting from lower nodes. Ligule an eciliate membrane.

Morphology Reproductive morphology Inflorescences

Inflorescence a panicle; embraced at base by subtending leaf. Panicle spiciform. Panicle axis bearing deciduous spikelet clusters. Spikelets subtended by an involucre. Fertile spikelets sessile; 1 in the cluster. Involucre composed of bristles; united into a herbaceous lobed scale. Involucral bristles deciduous with the fertile spikelets; flattened; rigid; obtuse.

Morphology Reproductive morphology Inflorescences Spikelets

Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate; dorsally compressed; 10-14 mm long; falling entire; deciduous with accessory branch structures.

Fertile

Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate; dorsally compressed; 10-14 mm long; falling entire; deciduous with accessory branch structures.

Morphology Reproductive morphology Inflorescences Bracts Glume

Glumes one the lower absent or obscure, or two; shorter than spikelet; thinner than fertile lemma. Lower glume ovate; hyaline; without keels; 0 -veined. Lower glume lateral veins absent. Upper glume ovate; 0.4-0.5 length of adjacent fertile lemma; herbaceous; without keels; 1-3 -veined. Upper glume apex acuminate.

Morphology Reproductive morphology Flowers Florets

Basal sterile florets male; with palea. Lemma of lower sterile floret lanceolate; herbaceous; 9 -veined; acute. Fertile lemma ovate; cartilaginous; much thinner above; without keel; 7 -veined. Lemma apex acute. Palea cartilaginous.

Morphology Reproductive morphology Flowers

Lodicules absent. Anthers 3. Stigmas 1.

Morphology Reproductive morphology Fruits

Caryopsis with adherent pericarp; oblong; dorsally compressed.

Distribution

Africa, or Temperate Asia.

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Morphology General Habit

Perennial. Rhizomes short. Culms erect; 50-120 cm long. Ligule a fringe of hairs.

Morphology Reproductive morphology Inflorescences

Dioecious. Inflorescence a panicle. Panicle spiciform. Panicle axis bearing deciduous spikelet clusters. Spikelets subtended by an involucre. Fertile spikelets sessile; 1 in the cluster. Male spikelets pedicelled. Involucre composed of bristles. Involucral bristles deciduous with the fertile spikelets; 7-12 in principal whorl; terete; flexible. Male inflorescence unlike female; a panicle. Male spikelets distinct from female; lanceolate. Male spikelet glumes 2.

Morphology Reproductive morphology Inflorescences Spikelets

Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate; dorsally compressed; 4-6 mm long; falling entire; deciduous with accessory branch structures.

Fertile

Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate; dorsally compressed; 4-6 mm long; falling entire; deciduous with accessory branch structures.

Morphology Reproductive morphology Inflorescences Bracts Glume

Glumes shorter than spikelet; thinner than fertile lemma. Lower glume ovate; membranous; without keels; 0-3 -veined. Lower glume apex entire, or erose; obtuse, or acute; muticous, or mucronate. Upper glume lanceolate, or ovate; membranous; without keels; 3-5 -veined. Upper glume apex obtuse, or acute.

Morphology Reproductive morphology Flowers Florets

Basal sterile florets barren; without significant palea. Lemma of lower sterile floret lanceolate; membranous; 5 -veined; acute, or acuminate; muticous, or mucronate. Fertile florets female. Fertile lemma lanceolate; coriaceous; without keel. Lemma surface striate. Lemma apex acute, or acuminate; pubescent. Palea coriaceous.

sex Male

Male inflorescence unlike female; a panicle. Male spikelets distinct from female; lanceolate. Male spikelet glumes 2.

Distribution

Australasia.