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.

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: 27th January 2014.