1	"Ocreae present, persistent or not; nodes generally swollen; flower cluster not subtended by involucre; pedicels all subtended by 2+ fused, membranous, wide bractlets (Polygonoideae)"	2
1	"Ocreae 0; nodes not swollen; flower clusters subtended by involucre of 1+ free or fused bracts (or not, in <i>Gilmania</i>); pedicels each often subtended by 2 free, transparent, linear bractlets (Eriogoneae-Eriogonoideae)"	11
2	"Perianth parts (5)6 (Rumiceae)"	3
2	"Perianth parts 4--5"	4
3	"Flowers unisexual, outer perianth parts of pistillate flower spine-tipped in fruit"	Emex
3	"Flowers generally bisexual, outer perianth parts not spine-tipped in fruit"	Rumex
4	"Perianth parts 4; fruit elliptic, 2-winged; leaves +- basal"	"Oxyria {Oxyria digyna}"
4	"Perianth parts 4--5; fruit generally ovoid; leaves generally cauline"	5
5	"Vine-like shrub; perianth in fruit fleshy (Coccolobeae)"	Muehlenbeckia
5	"Herb, or if shrub then not vine-like; perianth in fruit generally not fleshy (Polygoneae)"	6
6	"Outer perianth parts winged or keeled, or +- so"	7
6	"Outer perianth parts not winged or keeled"	8
7	"Flower base stalk-like; outer perianth parts winged (keeled in <i>Fallopia convolvulus</i>); leaf blade sagittate or cordate; ocrea papery, not 2-lobed distally"	Fallopia
7	"Flower base not stalk-like; outer perianth parts keeled; leaf blade not sagittate or cordate; ocrea generally translucent, 2-lobed distally"	Polygonum
8	"Leaves generally basal; inflorescence terminal, spike-like; stems not branched"	"Bistorta {Bistorta bistortoides}"
8	"Leaves cauline; inflorescence terminal, axillary, spike-like or not; stems generally branched"	9
9	"Ocreae generally translucent, glabrous, 2-lobed, fibrous in age"	Polygonum
9	"Ocreae opaque, glabrous to scabrous, not 2-lobed"	10
10	"Inflorescence raceme- or panicle-like; perianth parts fused +- 1/4; stamens 8"	Aconogonon
10	"Inflorescence +- head-, spike-, or panicle-like; perianth parts fused 1/4--2/3; stamens 5--8"	Persicaria
11	"Involucre bract 1, inflated, awns 0; leaves generally lobed; stamens 6 (Pterostegiinae)"	"Pterostegia {Pterostegia drymarioides}"
11	"Involucre 0 or tubular or of 2--5 +- free bracts, not inflated, awned or not; leaves entire; stamens 3--9 (Eriogoninae)"	12
12	"Annual to shrub, if annual then involucre tubular, awnless"	13
12	"Annual; involucres tubular and awned or of free or basally fused bracts, awned or not, 0 in <i>Gilmania</i>"	14
13	"Involucres of 2--5 awnless bracts"	"Dedeckera {Dedeckera eurekensis}"
13	"Involucres tubular"	Eriogonum
14	"Leaves basal and cauline, opposite"	"Goodmania {Goodmania luteola}"
14	"Leaves basal or if cauline then alternate or whorled"	15
15	"Involucre 0"	"Gilmania {Gilmania luteola}"
15	"Involucre present"	16
16	"Involucres of free or basally fused bracts"	17
16	"Involucres tubular"	20
17	"Stamens 3"	18
17	"Stamens 6 or 9"	19
18	"Perianth lobes leathery; involucre bracts 3, awned"	"Lastarriaea {Lastarriaea coriacea}"
18	"Perianth lobes petal-like; involucre bracts many, awnless"	Nemacaulis
19	"Involucre bracts 3(4), awned; plant tomentose"	"Hollisteria {Hollisteria lanata}"
19	"Involucre bracts 4--7, awnless; plant silky-puberulent"	"Johanneshowellia {Johanneshowellia puberula}"
20	"Involucre funnel- to bell-shaped, not angled, not ridged"	21
20	"Involucre generally +- cylindric, angled or not, ridged or not"	23
21	"Involucre awns 5(6); perianth lobes 3-lobed to fringed"	Sidotheca
21	"Involucre awns (3)4(5) or 7--36; perianth lobes generally entire"	22
22	"Involucre awns 4(5) or generally 7--30(36)"	Acanthoscyphus
22	"Involucre awns (3)4"	Oxytheca
23	"Bracts generally 2, opposite, or many, whorled; flowers 1(2)"	Chorizanthe
23	"Bracts 3, alternate, on 1 side of branch or not; flowers (1)2--6"	24
24	"Involucre teeth 5, awns at tips; flowers 4(6)"	"Aristocapsa {Aristocapsa insignis}"
24	"Involucre teeth 2--4 or 6, if 5 then awns both at base of involucre and at tips of teeth; flowers (1)2--3"	25
25	"Involucre not awned basally"	26
25	"Involucre awned basally"	27
26	"Flower hairy; bracts below involucre obvious; involucre teeth unequal"	Mucronea
26	"Flower glabrous, bumpy; bracts below involucre obscure; involucre teeth equal"	"Systenotheca {Systenotheca vortriedei}"
27	"Involucre 3-angled, basal awns 3, terminal (on teeth) 5; flowers 2"	"Centrostegia {Centrostegia thurberi}"
27	"Involucre 6-angled, basal awns 6, terminal (on teeth) 6; flowers 3"	"Dodecahema {Dodecahema leptoceras}"