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.

Themeda

HABIT Annual (3), or perennial (24). Rhizomes absent (26), or elongated (1). Culms erect (20/23), or geniculately ascending (7/23), or decumbent (1/23); robust (9/11), or slender (2/11); 15–152.2–600 cm long; firm (26), or wiry (1); without nodal roots (1/3), or with prop roots (2/3), or rooting from lower nodes (1/3). Culm-internodes terete (2/3), or elliptical in section (1/3). Lateral branches lacking (1/5), or ample (4/5). Ligule an eciliate membrane (9), or a ciliolate membrane (17), or absent (1). Leaf-blade base without a false petiole (26), or with a brief petiole-like connection to sheath (1). Leaf-blades linear, or lanceolate (1); stiff (2), or firm (23), or flaccid (2). Leaf-blade midrib conspicuous (2/5), or widened (3/5).

INFLORESCENCE Synflorescence simple (1), or compound (26); scanty (4/26), or linear (3/26), or paniculate (10/26), or fasciculate (9/26). Inflorescence composed of racemes; terminal (1), or terminal and axillary (26); not deciduous as a whole (25), or deciduous as a whole (2); subtended by a spatheole; exserted (3), or embraced at base by subtending leaf (2), or enclosed (23). Spatheole linear (6), or lanceolate (24), or ovate (1); scarious (25/25).

Racemes single; oblong (8), or ovate (1), or cuneate (18); bearing a triad of spikelets (2), or few fertile spikelets (25); bearing 1 fertile spikelets on each (14), or 2 fertile spikelets on each (17), or 3 fertile spikelets on each (3), or 4 fertile spikelets on each (2). Rhachis tough (2), or fragile at the nodes (25). Rhachis internodes indefinite (21), or linear (6).

Spikelets in pairs (17), or in threes (16). Fertile spikelets sessile; 1 in the cluster (26), or 2–3 in the cluster (1). Companion sterile spikelets pedicelled; 1 in the cluster (18), or 2 in the cluster (16). Pedicels linear (1), or oblong (26); tip oblique (11/11).

STERILE SPIKELETS Basal sterile spikelets represented by a single scale (1), or well-developed (26); forming an involucre about the fertile; persistent (25), or deciduous with the fertile (2).

Companion sterile spikelets well-developed; deciduous with the fertile (3), or separately deciduous (24). Companion sterile spikelet callus indistinct (1), or oblong (4), or linear (22).

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate (1), or elliptic (23), or oblong (3); subterete (22), or dorsally compressed (5); 2.5–7.134–17 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus brief (1), or square (1), or oblong (10), or cuneate (9), or linear (6); pubescent (4/24), or pilose (3/24), or bearded (17/24); base obtuse (9/26), or acute (5/26), or pungent (12/26); attached obliquely.

GLUMES Glumes exceeding apex of florets; firmer than fertile lemma. Lower glume lanceolate (2), or oblong (24), or ovate (1); chartaceous (1), or cartilaginous (1), or coriaceous (25); without keels; 1 -veined (1/12), or 5 -veined (2/12), or 6 -veined (1/12), or 7 -veined (4/12), or 8 -veined (3/12), or 9 -veined (5/12), or 10 -veined (1/12), or 11 -veined (4/12). Lower glume lateral veins absent (1), or distinct (26). Lower glume surface convex (21), or flat (3), or concave (1), or with a longitudinal median groove (2); smooth (23), or asperulous (2), or scabrous (2); without pits; glabrous (9), or puberulous (5), or pubescent (10), or pilose (2), or hirsute (2), or villous (1), or hispidulous (1). Lower glume apex truncate (6/18), or obtuse (10/18), or acute (2/18). Upper glume lanceolate (2), or oblong (25); chartaceous (2/16), or cartilaginous (1/16), or coriaceous (13/16); with undifferentiated margins (26), or membranous margins (1); 2-keeled (1/1); 3 -veined (14/14), or 4–5 -veined (1/14). Upper glume primary vein eciliate (25), or ciliate (2). Upper glume surface glabrous (24), or pubescent (1), or pilose (1), or villous (1). Upper glume apex truncate (4/5), or acute (1/5).

FLORETS Basal sterile florets barren; without significant palea. Lemma of lower sterile floret linear (1), or lanceolate (12), or elliptic (1), or oblong (11), or ovate (2); hyaline; 0 -veined (3/6), or 1 -veined (2/6), or 3–5 -veined (1/6); acute (1/1). Fertile florets bisexual (25), or female (2). Fertile lemma linear (21), or lanceolate (5), or oblong (1); hyaline; without keel; wingless; 1 -veined. Lemma surface unwrinkled; without grooves. Lemma apex acute (3/3); muticous (4), or awned (25); 1 -awned (25/25). Principal lemma awn straight (2/25), or geniculate (23/25), or bigeniculate (1/25). Column of lemma awn glabrous (2/23), or hispidulous (11/23), or puberulous (6/23), or pubescent (1/23), or hirtellous (2/23), or hirsute (1/23). Palea present (1), or absent or minute (26); hyaline (1/1).

FLOWER Lodicules 1 (1/2), or 2 (1/2). Anthers 3 (8/8).

FRUIT Caryopsis with adherent pericarp (1/1).

DISTRIBUTION Africa (3), or Temperate Asia (14), or Tropical Asia (22), or Australasia (5), or Pacific (6), or North America (1), or South America (2).

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