Flora of North America species comparison

3-800 cm, annual, usually not woody.

5-150 cm, herbaceous, hollow, usually erect or ascending, rarely sprawling, in the spring often spreading, sometimes decumbent in the fall, usually branching from the mid- or lower culm nodes in summer and fall;

branches rebranching 1-4 times, terminating in small secondary panicles that are usually partly included in the sheaths.

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.

3-14, usually distinctly longer and narrower than the rosette blades;

ligules of hairs, membranous, or membranous and ciliate, sometimes absent;

pseudoligules of 1-5 mm hairs often present at the bases of the blades immediately behind the true ligules;

blades usually distinctly longer and narrower than those of the basal rosette, cross sections with non-Kranz anatomy;

photosynthesis C3.

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.

panicles, terminal on the culms and branches;

sterile branches and bristles absent;

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.

0.8-5.2 mm, not subtended by bristles, dorsally compressed, surfaces unequally convex, apices unawned.

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.

apices not or only slightly gaping at maturity;

lower glumes 1/5 – 3/4 as long as the spikelets, 1-5-veined, truncate, acute, or acuminate;

upper glumes slightly shorter than the spikelets or exceeding the upper florets by up to 1 mm, 5-11-veined, not saccate, apices rounded to attenuate.

usually dorsally compressed or terete;

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

smooth;

pericarp thin;

endosperm hard;

hila round or oval, x = 9.

panicles terminating the culms, developing April-June (July), sometimes also in late fall, usually at least partially chasmogamous, often with a lower seed set than the secondary panicles;

secondary panicles terminating the branches, produced from (May)June to fall, usually partially or totally cleistogamous.

florets sterile or stami-nate;

lower lemmas similar to the upper glumes;

lower paleas sometimes present, thin, shorter than the lower lemmas;

upper florets bisexual, sessile, plump, usually apiculate to mucronate, sometimes minutely so, or subacute to (rarely) acute;

upper lemmas striate, chartaceous-indurate, shiny, usually glabrous, margins involute;

upper paleas striate;

lodicules 2;

anthers 3.

= 9, 10.