Flora of North America species comparison

3-800 cm, annual, usually not woody.

3-400 cm, erect, spreading or prostrate, sometimes trailing for 200+ cm.

open;

auricles sometimes present;

ligules membranous.

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, panicles of 1-many spikelike branches, these digitate or racemose on the rachis, spreading to erect, 1 or more branches completely or partially hidden in the sheaths in some species;

branch axes flattened, usually narrowly to broadly winged, usually terminating in a spikelet, sometimes extending beyond the distal spikelet but never forming a distinct bristle;

disarticulation below the glumes.

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.

subsessile to shortly pedicellate, plano-convex, rounded to acuminate, dorsally compressed, not subtended by bristles or a ringlike callus, solitary or paired (1 spikelet of the pair reduced in some species), in 2 rows along 1 side of the branches, with 2 florets, first rachilla segment not swollen, upper glumes and upper lemmas adjacent to the branch axes;

lower florets sterile;

upper florets sessile or stipitate, bisexual, acute or rounded.

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 present only on some spikelets of each branch, without veins or 1-veined, unawned;

upper glumes and lower lemmas subequal, membranous, apices rounded, unawned;

lower paleas absent or rudimentary;

upper lemmas convex, indurate, smooth to slightly rugose, stramineous to dark brown, margins scarious, involute, clasping the paleas;

upper paleas indurate, smooth to slightly rugose, stramineous to dark brown.

usually dorsally compressed or terete;

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

orbicular to elliptical, plano-convex or flattened, white, yellow, or brown, x = 10, 12.

= 9, 10.