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.

Dichanthium

HABIT Annual (5), or perennial (16). Rhizomes absent (20), or short (1). Culms erect (11/18), or geniculately ascending (7/18), or decumbent (4/18); of moderate stature (1/3), or slender (1/3), or weak (1/3); 10–55.35–150 cm long; firm (17), or wiry (4); rooting from lower nodes (2/2). Culm-internodes channelled (3/3). Lateral branches lacking (5/9), or sparse (3/9), or ample (3/9). Leaf-sheath auricles absent (20), or erect (1). Ligule an eciliate membrane (12), or a ciliolate membrane (9). Leaf-blades linear, or lanceolate (1); stiff (2), or firm (19); without exudate (20), or pruinose (1). Leaf-blade midrib evident (1/5), or conspicuous (2/5), or widened (2/5). Leaf-blade margins cartilaginous (3/3).

INFLORESCENCE Synflorescence simple (20), or compound (1); linear (1/1). Inflorescence composed of racemes; terminal (20), or terminal and axillary (1); subtended by an unspecialized leaf-sheath (19), or a spatheole (2); exserted (19), or embraced at base by subtending leaf (1), or enclosed (1). Spatheole linear (2/2); herbaceous (1/1). Peduncle widened at apex (1/1).

Racemes single (14), or paired (6), or digitate (12), or borne along a central axis (1); bearing 5–10 fertile spikelets on each (1/2), or 15–30 fertile spikelets on each (1/2). Rhachis fragile at the nodes; flattened (4/20), or subterete (16/20). Rhachis internodes filiform (9), or linear (12). Rhachis internode tip transverse (3/5), or oblique (2/5); flat (3/3). Raceme-bases brief (13), or filiform (8).

Spikelets in pairs. Fertile spikelets sessile; 1 in the cluster. Companion sterile spikelets pedicelled; 1 in the cluster. Pedicels filiform (9), or linear (12).

STERILE SPIKELETS Basal sterile spikelets absent (9), or well-developed (14).

Companion sterile spikelets well-developed; persistent (2/18), or separately deciduous (16/18).

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets lanceolate (2), or elliptic (10), or oblong (11), or obovate (2); dorsally compressed; 2–4.265–8.5 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus brief (19), or square (1), or cuneate (1); pubescent (6), or pilose (12), or bearded (3); base obtuse; attached transversely (18), or attached obliquely (3).

GLUMES Glumes exceeding apex of florets; firmer than fertile lemma. Lower glume lanceolate (1), or elliptic (8), or oblong (12), or ovate (1), or obovate (2); chartaceous (11), or cartilaginous (7), or coriaceous (3); without keels; wingless (18), or winged on keel (1), or winged on margins (2); 4 -veined (1/13), or 5 -veined (2/13), or 6 -veined (5/13), or 7 -veined (8/13), or 8 -veined (6/13), or 9 -veined (5/13), or 11 -veined (1/13). Lower glume lateral veins obscure (1), or distinct (20). Lower glume surface convex (11), or flat (6), or concave (6), or with a longitudinal median groove (1); smooth (17), or asperulous (1), or tuberculate (4); without pits (17), or pitted (4); glabrous (12), or pubescent (5), or pilose (5), or hirsute (1), or villous (1); without hair tufts (18), or with a transverse fringe of hair (5). Lower glume apex entire (19), or dentate (2); 3 -fid (1/1); truncate (5/15), or obtuse (9/15), or acute (7/15). Upper glume lanceolate (17), or elliptic (2), or oblong (2); membranous (1/5), or chartaceous (2/5), or cartilaginous (1/5), or coriaceous (1/5); with undifferentiated margins (20), or hyaline margins (1); without keels (3/20), or 1-keeled (17/20); 1 -veined (2/15), or 3 -veined (13/15). Upper glume primary vein eciliate (20), or ciliate (1). Upper glume surface smooth (20), or scabrous (1); glabrous (20), or pubescent (1). Upper glume apex entire (20), or erose (1); truncate (1/10), or acute (6/10), or acuminate (3/10); muticous (20), or mucronate (2).

FLORETS Basal sterile florets barren; without significant palea. Lemma of lower sterile floret linear (1/9), or lanceolate (1/9), or elliptic (2/9), or oblong (4/9), or ovate (3/9); hyaline; 0 -veined (7/8), or 3–5 -veined (1/8); obtuse (3/4), or acute (2/4). Fertile lemma linear; hyaline; without keel; wingless; 1 -veined (19/19). Lemma surface unwrinkled; without grooves. Lemma apex entire (20), or dentate (2), or lobed (1); 2 -fid (3/3); incised 0.2 of lemma length; awned; 1 -awned. Principal lemma awn apical (20), or from a sinus (3); geniculate. Column of lemma awn glabrous (19), or puberulous (2). Palea absent or minute.

FLOWER Anthers 2 (3/20), or 3 (17/20).

FRUIT Caryopsis with adherent pericarp (9/9); ellipsoid (1/5), or oblong (1/5), or obovoid (3/5). Embryo 0.5 length of caryopsis. Hilum punctiform (1/1).

DISTRIBUTION Africa (5), or Temperate Asia (5), or Tropical Asia (17), or Australasia (8), or Pacific (5), or North America (3), or South America (3).

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