Flora of North America species comparison

40-130 cm, to 1 mm thick at the nodes, unbranched, leafy for 50% of their height.

annual, sometimes becoming woody, internodes solid or hollow.

glabrous;

collars glabrous;

ligules 0.2-0.4 mm, entire;

blades (8)15-35(40) cm long, 3-8(11) mm wide, linear-lanceolate, usually glabrous, sometimes sparsely pilose adaxially.

distichous;

sheaths usually open;

auricles sometimes present;

abaxial ligules absent or of hairs;

adaxial ligules membranous, ciliate or not, or of hairs;

blades often pseudopetiolate;

mesophyll cells non-radiate;

adaxial palisade layer often present;

fusoid cells absent, but fusoidlike cells frequently present as extensions of the outer parenchyma bundle sheath;

arm cells absent;

kranz anatomy absent;

midrib simple;

adaxial bulliform cells present, large;

stomata with dome-shaped or triangular subsidiary cells;

bicellular microhairs present, with long, tapering apical cells;

papillae absent.

(7)12-35(47) cm, contracted, erect;

branches ascending to appressed;

axils of panicle branches glabrous;

pedicels 0.5-2.5 mm.

ebracteate, racemose or paniculate, panicle branches sometimes spikelike;

disarticulation below the spikelets or the florets, sometimes at the base of the pedicels.

4-9 mm long, 2-6 mm wide, with (2)3-5(7) florets, lower 1(2) florets sterile, fertile florets divergent to 45°.

bisexual or unisexual, often laterally compressed, with (1)2-many florets, reduced florets present, distal or basal to the functional florets.

shorter than the lemmas;

lemmas lacking uncinate hairs, usually 5-9-veined, unawned or with single, terminal awns;

paleas usually well-developed, sometimes short compared to the lemmas;

lodicules 2 or none, cuneate, usually well-vascularized, varying to not or scarcely vascularized;

stamens 2;

ovaries glabrous;

haustorial synergids presumed absent;

styles 2, sometimes fused at the base, if free, close.

1.3-3 mm, (1)3-5-veined;

upper glumes 1.3-2.5 mm, 3-5-veined;

calluses glabrous;

fertile lemmas 2.9-4.5 mm, straight, 3-7-veined, keels not winged, apices scabridulous;

paleas 2.3-3 mm;

anthers 1.3-1.5 mm, the length invariant within a spikelet.

1.9-2.2 mm, exposed at maturity.

basal, punctiform;

endosperm hard, without lipid;

starch grains simple;

embryos small or large relative to the caryopses;

epiblasts present;

scutellar cleft present;

mesocotyl internode present;

embryonic leaf margins overlapping, x = (11)12.

= 24.