Flora of North America species comparison

15-1000 cm, annual, herbaceous to somewhat woody, internodes usually hollow.

usually mostly cauline, often conspicuously distichous;

sheaths usually open;

auricles usually absent;

abaxial ligules usually absent (of hairs in Hakonechloa);

adaxial ligules membranous or of hairs, if membranous, often ciliate;

blades without pseudopetioles, sometimes deciduous at maturity;

mesophyll usually non-radiate (radiate in Amnio);

adaxial palisade layer absent;

fusoid cells absent;

arm cells usually absent (present in Phragmites);

Kranz anatomy absent;

midribs simple;

adaxial bulliform cells present;

stomatal subsidiary cells low dome-shaped or triangular;

bicellular microhairs usually present, usually with long, narrow terminal cells;

papillae usually absent.

usually terminal, ebracteate, usually paniculate, occasionally spicate or racemose.

laterally compressed, with 1-several bisexual florets or all florets unisexual and the species dioecious;

florets 1-several, terete or laterally compressed, distal florets often reduced;

disarticulation above the glumes.

2, from shorter than the adjacent lemmas to exceeding the distal florets;

lemmas (3)5-7-veined, lanceolate to elliptic, acute to acuminate, sometimes awned;

awns 1 or 3, if 3 not fused into a single basal column;

paleas subequal to the lemmas;

lodicules 2, usually free, occasionally joined at the base, fleshy, usually glabrous, not, scarcely, or heavily vascularized;

anthers (1)2-3;

ovaries glabrous;

styles 2, usually free, bases close together.

usually punctate (long-linear in Molinia);

endosperm hard, without lipid;

starch grains compound;

haustorial synergids absent;

embryos usually large compared to the caryopses, waisted or not;

epiblasts absent;

scutellar cleft present;

mesocotyl internode elongate;

embryonic leaf margins usually meeting (overlapping in Hakonechloa).

= 6,9, 10, 12.