1	"Flower, fruit enclosed in sac-like structure (perigynium); flowers unisexual"	2
1	"Flower, fruit not enclosed in sac-like structure; flowers bisexual or some staminate"	3
2	"Perigynium open at tip"	Carex
2	"Perigynium open on 1 side"	"Kobresia {Kobresia myosuroides}"
3	"Flower bracts 2-ranked; spikelets generally flat"	4
3	"Flower bracts spiraled (except <i>Isolepis levynsiana</i>); spikelets not flat (+- flat in <i>Isolepis levynsiana</i>)"	7
4	"Inflorescence in leaf axils; leaves cauline; stem internodes hollow"	"Dulichium {Dulichium arundinaceum var. arundinaceum}"
4	"Inflorescence terminal; leaves basal or basal and cauline; stem internodes solid or spongy with air cavities"	5
5	"Spikelets with >= 2 sterile proximal flower bracts; leaf sheaths +- black; inflorescence head-like"	"Schoenus {Schoenus nigricans}"
5	"Spikelets with 0--1 sterile proximal flower bracts; leaf sheaths not +- black; inflorescence head-like to openly branched"	6
6	"Spikelets with 2--36 flower bracts, each bract subtending a bisexual flower; fruits 2--many per spikelet"	Cyperus
6	"Spikelets with 2(3) flower bracts, proximal bract sterile or subtending a bisexual flower, distal sterile or subtending a staminate flower; fruits 1 per spikelet"	"Kyllinga {Kyllinga brevifolia}"
7	"Flower stems generally with cauline leaves 0 (1--2 cauline in <i>Schoenoplectus saximontanus</i>)"	8
7	"Flower stems with cauline leaves >= 1 (see also <i>Schoenoplectus saximontanus</i>)"	13
8	"Inflorescence bracts 0; spikelet 1; leaves 2, blade 0 or tooth-like, <= 1 mm; fruit tubercle generally present"	Eleocharis
8	"Inflorescence bracts >= 1; spikelets >= 1; leaves 1--3, generally some clearly bladed; fruit tubercle 0"	9
9	"Flower bract (outer if 2) with >= 3 veins; stem <= 40 cm"	10
9	"Flower bract with 1 vein, at least in distal-most part of spikelet; stem <= 400 cm"	11
10	"Flower bract 1 per flower"	Isolepis
10	"Flower bracts (1)2 per flower (a 2nd, inner bract between flower, spikelet axis generally present)"	Lipocarpha
11	"Stems <= 15 cm, < 1 mm diam; spikelets 1, 3--4.6 mm, 1.5--2.8 mm wide"	Trichophorum
11	"Stems (1)10--400 cm, <= 10 mm diam; spikelets 1--200, 3--23 mm, 2--7 mm wide"	12
12	"Ligule ciliate; stem, leaf air cavities 0; stem wiry; flower bracts shiny, in proximal part of spikelet 3--9-veined, at least in distal-most 1-veined, tip not notched"	"Amphiscirpus {Amphiscirpus nevadensis}"
12	"Ligule glabrous; stem, leaf generally with air cavities; stem rarely wiry; flower bracts dull, 1-veined, tip generally notched"	Schoenoplectus
13	"Inflorescences generally > 1, terminal and generally >= 1 axillary"	14
13	"Inflorescence 1, terminal"	16
14	"Flowers 10--50 per spikelet"	Scirpus
14	"Flowers < 6 per spikelet"	15
15	"Stem 5--10 mm diam; leaf blades 5--10 mm wide, margins saw-toothed"	"Cladium {Cladium californicum}"
15	"Stem <= 2 mm diam; leaf blades 0.5--5 mm wide, margins generally scabrous"	Rhynchospora
16	"Leaf sheath tip margins scabrous or ciliate; stem, leaf blades glabrous or generally +- scabrous or puberulent"	17
16	"Leaf sheath tip margins glabrous; stem, leaf blades glabrous or on keels or angles scabrous"	18
17	"Leaf sheath tip ciliate, hairs >> 1 mm, soft"	"Bulbostylis {Bulbostylis capillaris}"
17	"Leaf sheath tip scabrous, hairs << 1 mm, stiff"	Fimbristylis
18	"Stem cylindric; perianth bristles 10--25, smooth, >> fruit"	"Eriophorum {Eriophorum gracile}"
18	"Stem 3-angled; perianth bristles 3--6(--12), barbed, < to > fruit"	19
19	"Flower bracts puberulent (glabrous in age), tip notched, generally with curved awn often broken off; tubers durable"	Bolboschoenus
19	"Flower bracts glabrous, tip entire or sharp-pointed, awn 0 or minute; tubers 0"	20
20	"Inflorescence congested, head-like; perianth bristles > fruit"	Calliscirpus
20	"Inflorescence openly branched with head-like clusters at branch tips; perianth bristles <= fruit"	Scirpus