Flora of North America species comparison

3-800 cm, annual, usually not woody.

5-250 cm, erect or decumbent, branching basally or at aerial culm nodes, when annual or of indefinite duration usually decumbent and rooting at the lower nodes.

open;

ligules membranous, sometimes ciliate;

blades usually flat.

basal and/or cauline;

sheaths usually open;

ligules of hairs or membranous, membranous ligules often ciliate, cilia sometimes longer than the membranous base;

blades occasionally pseudopetiolate, seldom disarticulating at maturity.

terminal, sometimes also axillary, occasionally subterranean panicles;

branches sometimes spikelike and secund, sometimes less than 1 cm;

disarticulation usually below the glumes, sometimes at the base of the panicle branches, occasionally below the florets.

terminal, sometimes also axillary, usually panicles of 1-sided spikelike branches (sometimes only 1 branch) attached digitately or racemosely to a rachis, sometimes simple panicles of solitary, pedicellate spikelets; spikelike branches, if present, sometimes with secondary branches, primary branch axes triquetrous, bearing spikelets abaxially, in 2 rows, usually in unequally pedicellate groups of 2-5, occasionally borne singly.

usually dorsally compressed, varying to terete or laterally compressed, with 2(3) florets, lower florets staminate, sterile, or reduced, upper florets usually bisexual;

calluses not developed.

1.2-8.2 mm, lanceoloid to ellipsoid, dorsally compressed, apices obtuse to acuminate, unawned, with 2 florets;

disarticulation beneath the glumes.

usually membranous;

lower glumes usually less than 1/2 as long as the spikelets, sometimes absent;

upper glumes usually subequal to the upper florets, occasionally absent;

lower lemmas similar to the upper glumes in length and texture;

upper lemmas indurate, coriaceous, or cartilaginous, with a germination flap at the base, margins usually widely separated and involute at maturity, sometimes flat and hyaline;

upper paleas similar to the upper lemmas in length and texture;

lodicules short;

anthers usually 3;

stigmas usually red.

absent or to 1/4 as long as the spikelets;

upper glumes usually from 1/6 as long as to equaling the spikelets, occasionally absent, 0-5-veined, usually pubescent;

lower florets sterile;

lower lemmas membranous, usually as long as the upper lemmas, usually pubescent, (3)5-7(13)-veined;

lower paleas absent or reduced;

upper lemmas mostly stiffly chartaceous to cartilaginous, obscurely veined, with 0.5-1 mm hyaline margins that embrace the upper paleas;

upper paleas similar to the upper lemmas in texture and size;

lodicules 3, cuneate;

anthers 3.

usually dorsally compressed or terete;

embryos 1/2 or more the length of the caryopses.

plano-convex;

embryos 1/5–1/2 as long as the caryopses;

hila punctiform to ellipsoid, x = 9.

= 9, 10.