Mesosetum

HABIT Annual (7), or perennial (19). Rhizomes absent (21), or short (1), or elongated (4). Stolons absent (21), or present (5). Culms erect (18/25), or geniculately ascending (4/25), or decumbent (7/25), or prostrate (1/25); slender (11/11); 8–47.67–140 cm long; without nodal roots (3/9), or rooting from lower nodes (9/9). Lateral branches lacking (3/5), or sparse (2/5), or ample (2/5). Ligule a fringe of hairs. Leaf-blades filiform (4), or linear (22), or lanceolate (2); stiff (1), or firm (25). Leaf-blade midrib conspicuous (1/1). Leaf-blade margins unthickened (1/13), or cartilaginous (13/13).

INFLORESCENCE Inflorescence composed of racemes.

Racemes single; erect (1), or ascending (25); unilateral; bearing few fertile spikelets (1), or many spikelets (25); bearing 5–10 fertile spikelets on each (1/1). Rhachis wingless (18), or narrowly winged (3), or broadly winged (5); membranous (1/5), or herbaceous (2/5), or foliaceous (2/5); angular (20/21), or subterete (1/21). Spikelet packing adaxial; crowded (2), or contiguous (21), or lax (3); 1 -rowed (1/13), or 2 -rowed (12/13).

Spikelets appressed (1/1); solitary. Fertile spikelets sessile (7), or pedicelled (19). Pedicels free (18/20), or fused to internode (3/20); oblong (19/20), or reduced to a stump (1/20).

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets oblong (24), or ovate (1), or obovate (1); laterally compressed; symmetrical (25), or gibbous (1); 2.241–4.409–7 mm long; falling entire. Spikelet callus brief (25), or oblong (1); free from lower glume (25), or incorporating lowest rhachilla internode with adnate lower glume (1); glabrous (2), or pubescent (23), or pilose (1); base truncate (1/1).

GLUMES Glumes shorter than spikelet (15), or reaching apex of florets (11); thinner than fertile lemma (25), or firmer than fertile lemma (1). Lower glume linear (1), or lanceolate (18), or elliptic (1), or oblong (6); membranous (2), or chartaceous (23), or coriaceous (1); 1-keeled; wingless (25), or winged on keel (1); 1–2 -veined (1/25), or 3 -veined (24/25), or 4–5 -veined (4/25). Lower glume surface smooth (20), or asperulous (2), or scabrous (4); without pits; glabrous (18), or pubescent (1), or pilose (7), or villous (1); without hair tufts (24), or with a dorsal tuft of hair (2). Lower glume apex entire (19), or erose (1), or dentate (5), or lobed (1); 2 -fid (6/6); emarginate (4/20), or truncate (2/20), or obtuse (5/20), or acute (13/20), or acuminate (2/20), or attenuate (1/20), or setaceously attenuate (1/20); muticous (19), or mucronate (1), or awned (7). Upper glume lanceolate (23), or oblong (2), or ovate (1); not gibbous (25), or gibbous (1); membranous (23), or chartaceous (2), or coriaceous (1); without keels (24), or 1-keeled (2); wingless (25), or winged on keel (1); 3 -veined (9), or 4 -veined (3), or 5 -veined (19), or 6 -veined (3), or 7 -veined (4), or 8–9 -veined (1). Upper glume primary vein eciliate (25), or ciliate (1). Upper glume lateral veins without ribs (25), or ribbed (1); transversely connected at apex (3/3). Upper glume surface smooth (21), or asperulous (1), or scabrous (2), or rugose (2); glabrous (20), or pubescent (1), or pilose (7), or villous (1); without hair tufts (18), or with marginal tufts of hair (2), or with a dorsal tuft of hair (5), or with a transverse fringe of hair (1). Upper glume apex entire (24), or dentate (3); 2 -fid (3/3); emarginate (2/24), or obtuse (1/24), or acute (18/24), or acuminate (4/24); muticous (23), or mucronate (2), or awned (2); 1 -awned (2/2).

FLORETS Basal sterile florets male (8), or barren (19); with palea (14), or without significant palea (14). Lemma of lower sterile floret lanceolate (1), or oblong (23), or ovate (2); hyaline (2), or membranous (23), or cartilaginous (1); 3 -veined (6), or 4 -veined (4), or 5 -veined (22), or 6 -veined (1), or 7 -veined (3); without ribs (25), or ribbed (1); obtuse (2/25), or acute (21/25), or acuminate (1/25), or laterally pinched at apex (1/25); muticous, or mucronate (1). Fertile lemma ovate; laterally compressed (2), or dorsally compressed (24); membranous (1), or cartilaginous (1), or coriaceous (23), or indurate (1); of similar consistency on margins (25), or much thinner on margins (1); without keel (22), or keeled (4); wingless; 5 -veined (24/24). Lemma lateral veins obscure (4/4). Lemma surface smooth (24), or granulose (1), or striate (1); unwrinkled; without grooves. Lemma margins exposing palea (24), or covering most of palea (2); eciliate (25), or ciliolate (1). Lemma apex acute (20/25), or acuminate (5/25); without ornament (22), or pubescent (4). Palea membranous (1), or cartilaginous (1), or coriaceous (24); without keels (23), or 2-keeled (3).

FLOWER Anthers 3 (23/23).

FRUIT Caryopsis with adherent pericarp (1/1); ellipsoid (4/5), or obovoid (1/5); plano-convex (2/2). Embryo 0.33–0.5164–0.66 length of caryopsis. Hilum linear (22/22); 0.66–0.9838–1 length of caryopsis.

DISTRIBUTION North America (4), or South America.

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