1	"Sepals persistent after flower; flower parts in (3)4--5(7)s; hypanthium 0"	Ludwigia
1	"Sepals deciduous after flower (along with other flower parts); flower parts in (2)4s; hypanthium present, often elongate, or if 0 then petals rose-purple to pink, rarely white, or flowers bilateral"	2
2	"Stipules present, occasionally deciduous; fruit indehiscent, bur-like with hooked hairs; flower parts in 2s; stigmas maturing before anthers"	"Circaea {Circaea alpina subsp. pacifica}"
2	"Stipules 0; fruit generally dehiscent capsule, rarely indehiscent but not bur-like; flower parts in (3)4s; anthers generally maturing before stigmas"	3
3	"Seeds hair-tufted (tufts rarely secondarily lost); sepals erect; stigmas dry with multicellular papillae"	4
3	"Seeds not hair-tufted; sepals reflexed; stigmas mainly wet and nonpapillate or with dry unicellular papillae"	5
4	"Leaves generally alternate; hypanthium 0; petals entire; stamens +- equal, in 1 whorl; pollen blue-gray, grains shed singly"	Chamerion
4	"Leaves opposite at least at base; hypanthium 0.3--34 mm; petals notched; stamens in 2 unequal whorls; pollen cream, grains generally shed in 4s"	Epilobium
5	"Stigma 4-lobed, dry, papillae unicellular; anthers generally maturing before stigmas"	Clarkia
5	"Stigma hemispheric, peltate or 4-lobed, wet, papillae 0; anthers not maturing before stigmas"	6
6	"Fruit 2-chambered; stems slender, hair-like"	Gayophytum
6	"Fruit (3)4-chambered; stems generally not slender"	7
7	"Seeds with concave and convex sides, concave side with thick wing, both sides densely covered with club-shaped hairs; petals white, base yellow"	"Chylismiella {Chylismiella pterosperma}"
7	"Seeds generally not concave and convex, wing 0, club-shaped hairs 0; petals yellow, purple, red, or white, if white, generally lacking yellow base"	8
8	"Ovary tip projection 0.4--18 cm; stem 0"	9
8	"Ovary tip projection 0, occasionally +- tapering; stem generally present"	10
9	"Perennial herb; fruit cylindric-ovoid, +- straight or slightly curved, +- angled to nearly smooth, lacking pointed wing near center top of each valve, walls generally thin, distended by seeds; sterile projection of ovary persistent with fertile part in fruit, without abscission lines at juncture between hypanthium and fertile part of ovary"	Taraxia
9	"Annual; fruit irregularly obovoid, sharply 4-angled with pointed wing near center top of each valve, thick walled, not distended by seeds; sterile projection of ovary with clear abscission line at juncture between short hypanthium and fertile part of ovary"	Tetrapteron
10	"Stigma 4-lobed"	Oenothera
10	"Stigma hemispheric to spheric or cylindric"	11
11	"Seeds in 2 rows per chamber; fruit pedicelled; leaves often +- basal, pinnately lobed with large terminal lobe, occasionally either lateral lobes +- reduced or leaf ovate-cordate and long-petioled; abaxial leaf surface or margin with conspicuous (brown) oil cells"	Chylismia
11	"Seeds in 1 row per chamber; fruit sessile or occasionally short-pedicelled (<i>Camissonia kernensis</i>); leaves generally not predominately basal, entire to pinnately lobed and if so then terminal lobe not conspicuously larger than lateral; leaf oil cells 0"	12
12	"Petals white, pink, or rarely red; flowers night-blooming"	Eremothera
12	"Petals yellow, often with red flecks; flowers day-blooming"	13
13	"Flower stems wand-like; leaves pinnately lobed to occasionally entire; petals yellow with red flecks near base; seeds generally with purple spots; hypanthium with lobed disk"	"Eulobus {Eulobus californicus}"
13	"Flower stems not wand-like; leaves entire to toothed; petals yellow, occasionally with 2 red spots at base, or white; seeds without purple spots; hypanthium without lobed disk"	14
14	"Distal stem densely leafy, proximal stem nearly leafless; branches many, slender, ascending from base of pl; fruit strongly flattened, straight, 0.5--1 cm"	"Neoholmgrenia {Neoholmgrenia andina}"
14	"Stem generally leafy throughout, branched throughout or with a few basal branches; fruit cylindric to quadrangular, not flattened, often wavy or curled, (0.8)1--6 cm"	15
15	"Fruit +- cylindric; plants flower from distal nodes; leaves generally linear to narrowly elliptic; seeds glossy, triangular in &times;-section, often < 1 mm"	Camissonia
15	"Fruit 4-angled, at least when dry; plants generally flower from basal nodes; leaves generally narrowly lanceolate, narrowly elliptic or ovate; seeds dull, often > 1 mm, flattened"	Camissoniopsis