1	"Stem 0, internodes 0"	2
1	"Stem present, internodes short or long"	6
2	"Rhizomes thick, fleshy; plants without stolons"	"Viola nephrophylla"
2	"Rhizomes thin, not fleshy; plants with stolons, at least in summer"	3
3	"Fruit puberulent; leaf blade crenate; stolons green, leafy"	"Viola odorata"
3	"Fruit glabrous; leaf blade crenate to serrate; stolons pale, not leafy"	4
4	"Leaf blade lanceolate, narrowly ovate, or elliptic; petals white"	"Viola primulifolia subsp. occidentalis"
4	"Leaf blade reniform, ovate, or round; petals white or lilac to pale blue or +- white, with purple lines"	5
5	"Leaf blade glabrous to coarsely hairy; petals white; plants in dense patches"	"Viola macloskeyi"
5	"Leaf blade generally glabrous; petals lilac, pale blue, or +- white; plants not in dense patches"	"Viola palustris"
6	"Stipules +- = leaf; annual; lateral petals = or generally < sepals"	"Viola arvensis"
6	"Stipules << leaf; perennial herb; lateral petals >>sepals"	7
7	"Leaves compound"	8
7	"Leaves simple"	11
8	"Petals of 1 color, light gold- or deep lemon-yellow; cleistogamous flowers present or 0"	9
8	"Petals of 2 colors, upper dark red-violet, lower lilac, pale yellow, or cream to +- white; cleistogamous flowers 0"	10
9	"Leaf blades longer than wide; leaf segments 3--5, 1--2.5(5) mm wide; cleistogamous flowers 0; lateral 2 petals bearded with cylindric hairs"	"Viola douglasii"
9	"Leaf blades wider than long; leaf segments 3, 2--10 mm wide; cleistogamous flowers present, exclusively or not; lateral 2 petals +- bearded or not with club-shaped hairs"	"Viola sheltonii"
10	"Lower 3 petals (apart from veins, spots) lilac to +- white; leaves generally puberulent (glabrous)"	"Viola beckwithii"
10	"Lower 3 petals (apart from veins, spots) pale yellow, cream, or +- white, deep yellow to orange basally; leaves glabrous except veins, margins generally ciliate, stipules occasionally ciliate"	"Viola hallii"
11	"Lower stem erect, without leaves, peduncles"	12
11	"Lower stem prostrate to erect, with leaves, peduncles"	14
12	"Upper 2 petals deep lemon-yellow abaxially; stem green; cauline leaf ovate to deltate, entire; moist to wet generally shady places"	"Viola glabella"
12	"Upper 2 petals dark red-brown abaxially; stem generally purple; cauline leaf reniform, deltate, +- ovate, or diamond-shaped, deeply divided or not; generally dry shady or open places"	13
13	"Cauline leaf diamond-shaped, reniform-cordate, or generally deltate, not lobed or dissected"	"Viola lobata subsp. integrifolia"
13	"Cauline leaf +- ovate, deltate, or generally reniform, palmately lobed or deeply dissected"	"Viola lobata subsp. lobata"
14	"Plant with stolon-like stem; leaves evergreen"	"Viola sempervirens"
14	"Plant without stolon-like stem; leaves deciduous"	15
15	"Petals white at least adaxially, lateral with large purple spot basally above smaller yellow area"	16
15	"Petals not white"	17
16	"Leaf generally shiny, cauline leaf base wedge-shaped; plant glabrous"	"Viola cuneata"
16	"Leaf not shiny, cauline leaf base +- cordate to truncate; plant +- glabrous to generally puberulent"	"Viola ocellata"
17	"Petals light to deep violet, lavender, or blue-violet"	18
17	"Petals yellow to orange"	20
18	"Rhizome fleshy; style head glabrous; sepals not ciliate"	"Viola langsdorffii"
18	"Rhizome woody; style head bearded; sepals ciliate or not"	19
19	"Leaf ovate to ovate-triangular, entire to crenate; sepals not ciliate; spur generally longer than wide, straight or tip hooked; CA-FP, Wrn"	"Viola adunca subsp. adunca"
19	"Leaf ovate to reniform, crenate; sepals ciliate or not; spur +- as long as wide, straight, tip not hooked; KR (near Joe Bar, Siskiyou Co.)"	"Viola howellii"
20	"Petals gold-yellow, lowest 10--20 mm; basal leaf 0 per caudex; cleistogamous flower 0"	"Viola pedunculata"
20	"Petals deep lemon-yellow, lowest 6--16 mm; basal leaf 1--6 per caudex; cleistogamous flower present (0 in <i>Viola tomentosa</i>)"	21
21	"Fruit glabrous to minutely puberulent"	22
21	"Fruit puberulent to tomentose"	24
22	"Basal leaf blade base generally +- truncate"	"Viola praemorsa subsp. praemorsa"
22	"Basal leaf blade base generally tapered, obliquely so or not"	23
23	"Leaf generally entire"	"Viola bakeri"
23	"Leaf +- entire, +- crenate, serrate, wavy, or generally irregularly toothed"	"Viola praemorsa subsp. linguifolia"
24	"Basal leaves entire; cleistogamous flowers 0; fruit tomentose; n-c SNH"	"Viola tomentosa"
24	"Basal leaves not entire (<i>Viola purpurea</i> subsp. <i>integrifolia</i>, <i>Viola pinetorum</i> subsp. <i>pinetorum</i> occasionally entire); cleistogamous flowers present; fruit puberulent"	25
25	"Leaves canescent to tomentose"	26
25	"Leaves +- glabrous to puberulent"	27
26	"Basal leaves oblanceolate to obovate or generally linear to narrowly lanceolate, canescent to gray-tomentose; s SNH, Teh, WTR, SnBr"	"Viola pinetorum subsp. grisea"
26	"Basal leaves oblong, ovate, or round, green-tomentose; SNE, DMoj"	"Viola purpurea subsp. aurea"
27	"Stems mostly buried, not much elongated by end of season; plant 3--8.5(12) cm"	28
27	"Stems generally not buried, generally elongated by end of season; plant 3--25(34.5) cm"	29
28	"Cauline leaves generally entire, puberulent; basal leaves +- crenate to irregularly shallowly dentate or entire, unlobed; NW, CaR, n&c SNH"	"Viola purpurea subsp. integrifolia"
28	"Cauline leaves coarsely crenate or dentate, +- glabrous; basal leaves coarsely serrate or generally irregularly dentate or crenate with 2--4 rounded lobes per side; NCoRH, NCoRI, SnGb, GB, DMtns (Panamint Range)"	"Viola purpurea subsp. venosa"
29	"Basal leaf bases cordate to truncate"	30
29	"Basal leaf bases tapered"	33
30	"Basal leaf generally gray-green, occasionally purple-tinted abaxially"	31
30	"Basal leaf generally purple-tinted, occasionally gray-green abaxially"	32
31	"Basal leaf with 4--5(6) prominent lobes per side; TR, PR, SNE, DMoj"	"Viola purpurea subsp. mohavensis"
31	"Basal leaf without prominent lobes; CaR, SN, CW, SW, MP"	"Viola purpurea subsp. quercetorum"
32	"Cauline leaf not prominently lobed; basal petiole 1.8--8.5 cm; peduncle 4.6--6 cm; n SNH, GB"	"Viola purpurea subsp. dimorpha"
32	"Cauline leaf with 3--4(5) prominent lobes per side; basal petiole 4.5--14.5 cm; peduncle 1.7--14 cm; TR, PR, SNE, DMoj"	"Viola purpurea subsp. mohavensis"
33	"Basal leaf generally gray-green, occasionally purple-tinted abaxially"	"Viola purpurea subsp. quercetorum"
33	"Basal leaf generally purple-tinted abaxially"	34
34	"Cauline leaf 2--10 &times; longer than wide"	35
34	"Cauline leaf generally < 2 &times; longer than wide"	36
35	"Cauline leaf blade 3.5--9.6 cm, serrate or dentate with 2--4 short projections per side to +- entire; CaR, SN, WTR, SnBr, SnJt"	"Viola pinetorum subsp. pinetorum"
35	"Cauline leaf blade 1.5--4.8 cm, wavy, shallowly dentate, sharp-angled, or entire; CaR, SNH, WTR, SnBr, SnJt"	"Viola purpurea subsp. mesophyta"
36	"Basal leaf with 4--5(6) prominent lobes per side, not shiny adaxially; TR, PR, SNE, DMoj"	"Viola purpurea subsp. mohavensis"
36	"Basal leaf without prominent lobes, occasionally shiny adaxially; NW, CaR, SN, CW, SW, MP"	"Viola purpurea subsp. purpurea"