Flora of North America species comparison

fibrous, principally adventitious.

yellowish or brown, without trace of red or purple at base.

(culms) usually trigonous, occasionally terete, rarely compressed, usually solid, rarely hollow or septate.

basal sheaths fibrous or not;

sheath fronts membranous;

blades M-shaped in cross section when young, glabrous.

basal and/or cauline, alternate, usually 3-ranked, rarely 2-ranked or multi-ranked, bases forming cylindric sheaths enclosing stem, margins usually fused;

junction of sheaths and blades often with adaxial flaps of tissue or fringes of hair (ligules);

blades frequently absent from some basal leaves, rarely from cauline leaves, when present divergent or ascending, flat, folded, plicate, rolled, or terete, linear, venation parallel.

racemose, with 2–6 spikes;

proximal bracts leaflike, sheathing, sheath 4+ mm, longer than diameter of stem;

lateral spikes pistillate or distal lateral spike androgynous, pedunculate, prophyllate;

terminal spike staminate.

hypogynous, bisexual in most genera, unisexual in Scleria, Carex, Cymophyllus, and Kobresia;

perianth absent or with (1–)3–6(–30) bristles and/or scales, usually falling off with fruit;

stamens usually (1–)3, rarely more, usually distinct;

anthers basifixed;

pistils 1, 2–3(–4)-carpellate, fused, locule 1;

style undivided or branches 2–3(–4);

stigma sometimes papillate.

spreading to somewhat reflexed, rarely ascending, veined, stipitate, ovate or lanceolate, round or rounded-trigonous in cross section, base round-tapering, apex tapering or, rarely, contracted to beak, glabrous;

beak, when present, bidentate, teeth erect.

achenes, usually trigonous or biconvex;

pericarps thin (except in Scleria).

brown, oblong-ovoid or ovoid, trigonous, smaller than bodies of perigynia, smooth;

style persistent.

1;

testa thin, free from pericarp;

embryo basal;

endosperm abundant.

pistillate scales with 5–7-veined center, apex acute to awned.

3.

inflorescences (spikelets) a shortened axis; glumaceous bracts (scales) 1–many, spirally arranged, sometimes 2-ranked, usually appressed or ascending;

scales usually all fertile, each subtending a single flower, sometimes proximal and/or distal scales empty;

lateral spikes often with basal, usually empty, usually 2-keeled scale (prophyll); occasionally prophyll subtending and enclosing rachilla, bearing 1 pistillate, sometimes (0–)3 staminate flowers and empty scales (Carex, Cymophyllus, and Kobresia).

inflorescences panicles, often modified to corymb, pseudoumbel, cyme (anthela), raceme, spike, or capitulum (head), rarely single spike, usually subtended by foliaceous or, less frequently, glumaceous bracts;

secondary inflorescences sometimes simulating spikelets (Carex, Cymophyllus, and Kobresia).

= 5–ca. 100.