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.

Dimeria

HABIT Annual (44), or perennial (13). Stolons absent (55), or present (2). Culms erect (36/41), or geniculately ascending (12/41), or decumbent (5/41); slender (19/19); 5–32.25–120 cm long; without nodal roots (2/5), or rooting from lower nodes (5/5). Lateral branches lacking (9/16), or sparse (5/16), or ample (3/16). Leaves differentiated into sheath and blade (56), or without demarcation between sheath and blade (1). Ligule an eciliate membrane (18), or a ciliolate membrane (39). Leaf-blades linear (56), or lanceolate (16); stiff (2), or firm (52), or flaccid (3). Leaf-blade midrib evident (1/4), or conspicuous (3/4). Leaf-blade margins cartilaginous (3/3).

INFLORESCENCE Inflorescence composed of racemes; not deciduous as a whole (56), or deciduous as a whole (1); subtended by an unspecialized leaf-sheath (54), or an inflated leaf-sheath (3); exserted (56), or embraced at base by subtending leaf (1). Peduncle widened at apex (1/1).

Racemes single (20), or paired (36), or digitate (16); side by side (42/43), or intertwined (1/43); appressed (1), or erect (5), or ascending (53); unilateral; bearing few fertile spikelets (1), or many spikelets (56); bearing 2–7 fertile spikelets on each (1/1). Rhachis persistent (42/43), or deciduous from axis (1/43); wingless (37), or narrowly winged (15), or broadly winged (5); flattened (28/48), or angular (17/48), or subterete (4/48). Spikelet packing crowded (43), or contiguous (11), or lax (3); 2 -rowed (52/52). Raceme-bases brief (56), or filiform (1); unequal (the longer measured) (1/1).

Spikelets appressed (54/56), or ascending (1/56), or spreading (1/56); solitary. Fertile spikelets sessile (5), or pedicelled (52). Pedicels linear (1/50), or oblong (3/50), or clavate (2/50), or cuneate (31/50), or reduced to a stump (13/50).

FERTILE SPIKELETS Spikelets comprising 1 basal sterile florets; 1 fertile florets; without rhachilla extension. Spikelets linear (2), or lanceolate (5), or elliptic (23), or oblong (29), or ovate (4), or obovate (1), or oblanceolate (2); laterally compressed; 1–4.618–12 mm long; falling entire; deciduous from the base (56), or with accessory branch structures (1). Spikelet callus brief (41), or square (7), or oblong (6), or cuneate (3); glabrous (1/49), or pubescent (31/49), or pilose (9/49), or bearded (10/49); base truncate (6/50), or obtuse (44/50), or acute (2/50), or pungent (1/50); attached obliquely (1/1).

GLUMES Glumes shorter than spikelet (1), or reaching apex of florets (2), or exceeding apex of florets (54); firmer than fertile lemma; parallel to lemmas (56), or recurved at apex (1). Lower glume linear (18), or lanceolate (6), or elliptic (22), or oblong (24); chartaceous (10), or coriaceous (47); without keels (2), or 1-keeled (55); wingless (40), or winged on keel (17), or winged on margins (1); 1 -veined (2/16), or 3 -veined (14/16). Lower glume lateral veins absent (2), or distinct (55). Lower glume surface smooth (46), or asperulous (6), or scabrous (5); without pits; glabrous (43), or puberulous (1), or pubescent (9), or pilose (6). Lower glume apex emarginate (1/56), or obtuse (6/56), or acute (29/56), or acuminate (17/56), or attenuate (3/56), or setaceously attenuate (3/56); muticous (55), or mucronate (3). Upper glume lanceolate (13), or elliptic (37), or oblong (21), or ovate (3); 5.5–5.75–6 length of adjacent fertile lemma; chartaceous (8), or coriaceous (54); with undifferentiated margins (25), or hyaline margins (32); without keels (5), or 1-keeled (52); wingless (16), or winged on keel (42), or winged on margins (1); 1 -veined (3/18), or 3 -veined (15/18). Upper glume primary vein eciliate (25), or ciliolate (3), or ciliate (30). Upper glume surface smooth (48), or asperulous (5), or scabrous (3), or rugose (1); glabrous (39), or puberulous (1), or pubescent (4), or pilose (12), or hirsute (1), or villous (2), or hispid (1). Upper glume apex emarginate (1), or obtuse (4), or acute (28), or acuminate (25), or attenuate (3), or setaceously attenuate (2); muticous (48), or mucronate (2), or awned (7); 1 -awned (7/7).

FLORETS Basal sterile florets barren (55/55); without significant palea (55/55). Lemma of lower sterile floret linear (2/54), or lanceolate (44/54), or elliptic (2/54), or oblong (9/54), or obovate (1/54); hyaline (54/54); 0 -veined (3/19), or 1 -veined (13/19), or 2 -veined (3/19); obtuse (2/9), or acute (7/9). Fertile lemma lanceolate (2), or elliptic (44), or oblong (9), or ovate (1), or obovate (1), or oblanceolate (3); hyaline (31/34), or membranous (2/34), or cartilaginous (1/34); without keel; wingless; 1 -veined (52/52). Lemma surface smooth (56), or papillose (1); unwrinkled; without grooves. Lemma margins eciliate (55), or ciliolate (2), or ciliate (1). Lemma apex entire (1), or dentate (56); 2 -fid (56/56); muticous (1), or mucronate (1), or awned (56); 1 -awned (56/56). Principal lemma awn apical (1), or from a sinus (56); straight (3), or curved (1), or geniculate (55); limb glabrous (56), or puberulous (1). Column of lemma awn glabrous (55/56), or puberulous (1/56). Palea present (11), or absent or minute (46); hyaline (3/11), or membranous (8/11); 0 -veined (1/1). Palea keels smooth (9/11), or tuberculate (2/11); eciliate (10/11), or ciliate (1/11). Palea surface glabrous (9/11), or pilose (2/11).

FLOWER Lodicules 2 (18/18); fleshy (1/1); glabrous (17/18), or ciliate (1/18); truncate (2/2). Anthers 2 (54/54). Stigmas 2 (1/1).

FRUIT Caryopsis with adherent pericarp (19/19); linear (2/18), or lanceolate (1/18), or ellipsoid (4/18), or oblong (14/18); isodiametric (1/3), or laterally compressed (2/3). Embryo 0.5 length of caryopsis. Hilum punctiform (2/2).

DISTRIBUTION Africa (3), or Temperate Asia (6), or Tropical Asia (49), or Australasia (3), or Pacific (3).

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