Flora of North America species comparison

fibrous, principally adventitious.

reclining or drooping, 19–51 cm × 0.2–0.7 mm.

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

basal sheaths purple;

nonbasal sheaths with traces of purple, 7–40 mm;

blades erect, ascending, or decumbent, green, 17–45 cm × (2–)3–6(–7) mm.

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.

spikes (3–)4(–5) per culm, scattered;

peduncle of lateral pistillate spikes slender, drooping, 8–11 cm, distal peduncle shortest;

bracts reduced, 0.6–1.5 cm.

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.

2–6 per spike, overlapping, finely veined, orbicular, 2.8–3.2 × 1.8–2.1 mm;

beak tapering.

slightly bent from achene.

achenes, usually trigonous or biconvex;

pericarps thin (except in Scleria).

orbicular, 1.8–2 × 1.8–2 mm, sides slightly concave at maturity, tightly fitting in perigynia.

1;

testa thin, free from pericarp;

embryo basal;

endosperm abundant.

spikes the proximal basal, 7–12 × 4–6 mm.;

pistillate scales keeled, 2.5–3.7 × 1.5–2 mm, midribs green, margins hyaline, purple outward, apex aristate.

spike 1, linear, long-pedunculate, 0.7–2 × 2–4 mm.;

staminate scales obtuse, 3–5 × 0.8–1.1 mm, midribs green, margins hyaline and purple.

3–3.2 mm.

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.

= 60.