Bouteloua

HABIT Annual (4), or perennial (21). Rhizomes absent (23), or short (1), or elongated (1). Stolons absent (22), or present (5). Culms erect (12/16), or geniculately ascending (6/16), or decumbent (4/16), or rambling (2/16); slender (6/8), or weak (2/8); 5–45.14–200 cm long. Lateral branches sparse (1/2), or ample (1/2). Ligule an eciliate membrane (1), or a ciliolate membrane (2), or a ciliate membrane (3), or a fringe of hairs (19). Leaf-blades filiform (1), or linear (24); stiff (4), or firm (21).

INFLORESCENCE Inflorescence composed of racemes; exserted, or embraced at base by subtending leaf (2).

Racemes borne along a central axis; erect (1), or ascending (19), or spreading (4), or deflexed (4); linear (16), or oblong (1), or cuneate (8); unilateral; bearing 1 spikelet (4), or few fertile spikelets (12), or many spikelets (9); bearing 1–5–20 fertile spikelets on each. Central inflorescence axis unspecialized (24), or flattened (1); tip without extension (8), or subulate (14), or filiform (3). Rhachis deciduous from axis; flattened (4), or angular (17), or subterete (4); terminating in a barren extension; extension subulate (18), or bristle-like (5), or a forked bristle (2). Spikelet packing broadside to rhachis; contiguous (22), or lax (3). Raceme-bases brief (23), or linear (2).

Spikelets appressed (19), or ascending (5), or pectinate (1); solitary. Fertile spikelets sessile.

STERILE SPIKELETS Basal sterile spikelets absent (21), or rudimentary (1), or well-developed (3); persistent (3/4), or deciduous with the fertile (1/4).

FERTILE SPIKELETS Spikelets comprising 1 fertile florets; with a barren rhachilla extension (1), or with diminished florets at the apex. Spikelets lanceolate (3), or elliptic (1), or cuneate (21); laterally compressed; 2.5–6.439–12 mm long; falling entire; deciduous with accessory branch structures. Spikelet callus glabrous (1/3), or pubescent (1/3), or pilose (2/3). Floret callus glabrous (1/3), or pubescent (1/3), or pilose (1/3), or bearded (1/3).

GLUMES Glumes shorter than spikelet (15), or reaching apex of florets (10), or exceeding apex of florets (4); thinner than fertile lemma (21), or similar to fertile lemma in texture (4); parallel to lemmas (4), or gaping (21). Lower glume subulate (1), or linear (2), or lanceolate (22); 0.3–0.6486–1 length of upper glume; membranous; 1-keeled (24/24); 1 -veined. Lower glume lateral veins absent. Lower glume surface smooth, or asperulous (1), or scabrous (1); without pits; glabrous (20), or puberulous (1), or pubescent (4), or villous (1), or hispidulous (1), or hispid (1). Lower glume apex acute (10/24), or acuminate (19/24), or attenuate (6/24), or setaceously attenuate (6/24); muticous (24/24), or mucronate (1/24). Upper glume lanceolate (24), or elliptic (1); 0.6–0.9156–1.3 length of adjacent fertile lemma; membranous; 1-keeled; 1 -veined. Upper glume primary vein eciliate (23), or ciliate (2). Upper glume surface smooth, or asperulous (1), or scabrous (1); glabrous (20), or puberulous (1), or pubescent (4), or villous (1), or hispidulous (1), or hispid (1). Upper glume apex entire (23), or dentate (2); 2 -fid (2/2); acute (9/23), or acuminate (20/23), or attenuate (5/23), or setaceously attenuate (4/23); muticous (23), or mucronate (1), or awned (2); 1 -awned (2/2).

FLORETS Fertile lemma lanceolate (5), or elliptic (2), or oblong (1), or ovate (17); membranous (5), or cartilaginous (1), or coriaceous (19); without keel (2), or keeled (23); wingless; 3 -veined. Lemma surface smooth (23), or asperulous (1), or scabrous (2); unwrinkled; without grooves; glabrous (19), or puberulous (5), or pubescent (4), or villous (1); hairy on back (8/10), or on veins (1/10), or in lines (1/10). Lemma apex entire (6), or dentate (18), or lobed (2); 3 -fid (20/20); incised 0.33 of lemma length; acute (5/6), or acuminate (1/6); muticous (5), or mucronate (8), or awned (14); 2 -awned (1/20), or 3 -awned (19/20). Principal lemma awn apical (18/21), or from a sinus (3/21). Lateral lemma awns subequal to principal (8/14), or shorter than principal (6/14). Palea 0.8–0.9–1 length of lemma. Palea keels eciliate (24), or puberulous (1). Palea surface glabrous (22), or pubescent (2), or villous (1). Palea apex muticous (16), or with excurrent keel veins (8), or awned (2). Apical sterile florets 1 in number (24), or 2 in number (3), or 3 in number (1); male (4), or barren (21); separate (23), or in a clump (2); rudimentary (15), or linear (1), or lanceolate (2), or oblong (7), or cuneate (1). Apical sterile lemmas muticous (1), or awned. Apical sterile lemma awns glabrous (23), or ciliate (2).

FLOWER Anthers 3 (7/7).

FRUIT Caryopsis with adherent pericarp; ellipsoid (2/12), or oblong (1/12), or ovoid (5/12), or obovoid (4/12). Embryo 0.5–0.7339–0.9 length of caryopsis.

DISTRIBUTION North America (22), or South America (13).

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