Echinochloa

HABIT Annual (23/32), or perennial (10/32). Rhizomes absent (29), or elongated (4). Culms erect (18/29), or geniculately ascending (14/29), or decumbent (8/29), or prostrate (1/29), or rambling (1/29); reed-like (1/7), or robust (5/7), or of moderate stature (1/7), or slender (1/7); 10–105.5–400 cm long; spongy (3), or compressible (3), or firm (27), or wiry (1); without nodal roots (4/7), or rooting from lower nodes (7/7). Culm-internodes terete (2/3), or channelled (1/3). Culm-nodes swollen (1/1). Lateral branches lacking (4/6), or sparse (4/6), or ample (1/6). Ligule a fringe of hairs (19), or absent (15). Leaf-blades linear, or lanceolate (1); stiff (1), or firm (32). Leaf-blade midrib conspicuous (4/4). Leaf-blade margins cartilaginous (7/7).

INFLORESCENCE Inflorescence composed of racemes; exserted (32), or embraced at base by subtending leaf (1).

Racemes borne along a central axis; not compacted (32), or in a multilateral false spike (1); appressed (6), or erect (7), or ascending (26), or spreading (2); unilateral; bearing 10–30 fertile spikelets on each (1/1). Rhachis wingless (31), or narrowly winged (2); angular (23), or subterete (10). Spikelet packing adaxial (1/1); crowded (14), or contiguous (17), or lax (2); 2 -rowed (6), or 3 -rowed (5), or 4 -rowed (31), or 5 -rowed (4), or 6 -rowed (3).

Spikelets appressed (1/1); solitary (3), or in pairs (30), or in threes (2), or clustered at each node (5). Fertile spikelets sessile (17), or sessile and pedicelled (4), or pedicelled (12); 2–4 in the cluster (5/5); subequal (17/17). Pedicels oblong (3/3); tip discoid (7/7).

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets elliptic (22), or ovate (15), or orbicular (3), or obovate (1); dorsally compressed; symmetrical (10), or gibbous (20), or turgidly plano-convex (1), or plano-convex (2); 1.5–4.176–7.5 mm long; persistent on plant (2), or falling entire (31). Spikelet callus brief (29), or oblong (3), or globular (1); free from lower glume (29), or incorporating lowest rhachilla internode with adnate lower glume (4). Rhachilla internodes brief up to lowest fertile floret (32), or elongated between glumes (1).

GLUMES Glumes reaching apex of florets; thinner than fertile lemma. Lower glume ovate (32), or oblate (1); clasping (19/19); membranous (16/16), or chartaceous (2/16); without keels; 3 -veined (22/31), or 4 -veined (18/31), or 5 -veined (26/31), or 6 -veined (2/31), or 7 -veined (3/31). Lower glume surface smooth (16), or asperulous (3), or scabrous (15), or spinose (2); without pits; glabrous (21), or pubescent (3), or hispidulous (7), or hispid (5). Lower glume apex obtuse (3), or acute (13), or acuminate (6), or cuspidate (17); muticous (32), or mucronate (1). Upper glume elliptic (9), or ovate (25); not gibbous (32), or gibbous (1); membranous (31), or chartaceous (2); without keels; 3–4 -veined (2), or 5 -veined (29), or 6 -veined (6), or 7 -veined (8), or 9 -veined (2). Upper glume surface smooth (23), or asperulous (1), or scabrous (7), or spinose (4); glabrous (10), or puberulous (1), or pubescent (4), or hispidulous (16), or hispid (6); with simple hairs (23/25), or tubercle-based hairs (4/25). Upper glume apex obtuse (2/32), or acute (3/32), or acuminate (10/32), or cuspidate (19/32), or caudate (1/32); muticous (29), or mucronate (4), or awned (9); 1 -awned (9/9).

FLORETS Basal sterile florets male (18), or barren (20); with palea (28), or without significant palea (7). Lemma of lower sterile floret elliptic (8), or ovate (25); membranous (31), or chartaceous (3); 3–4 -veined (1), or 5 -veined (28), or 6 -veined (8), or 7 -veined (12), or 9 -veined (1); without grooves (32), or sulcate (1); obtuse (3), or acute (7), or acuminate (18), or attenuate (1), or cuspidate (9); muticous (19), or mucronate (1), or awned (23). Fertile lemma elliptic (8), or oblong (1), or ovate (24), or orbicular (1); not gibbous (7), or gibbous (26); coriaceous (1), or indurate (32); of similar consistency above (4), or much thinner above (29); without keel; wingless; 5 -veined (22/22). Lemma lateral veins obscure (3/3). Lemma surface smooth (31), or striate (3); unwrinkled; without grooves. Lemma margins involute. Lemma apex obtuse (2), or acute (15), or acuminate (2), or cuspidate (7), or apiculate (4), or rostrate (3); without ornament (7), or laterally pinched (25), or scabrous (1); muticous (32), or mucronate (1). Palea reflexed at apex; 1 length of lemma; coriaceous (1), or indurate (32).

FLOWER Anthers 3.

FRUIT Caryopsis with adherent pericarp (13/13); ellipsoid (4/7), or oblong (4/7), or ovoid (1/7), or orbicular (1/7). Embryo 0.5–0.6857–0.8 length of caryopsis.

DISTRIBUTION Europe (4), or Africa (16), or Temperate Asia (7), or Tropical Asia (9), or Australasia (17), or Pacific (5), or North America (11), or South America (11).

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