1	Anthers coherent only at base.		(2)
+	Anthers coherent into a tube.		(8)
2 (1)	Corolla 2-2.5 cm; filaments inserted at or above middle of corolla tube.		(3)
+	Corolla 0.7-1.6 cm; filaments inserted below middle of corolla tube.		(5)
3 (2)	Corolla blue, purple, or light purple-red		1 Onosma hookeri
+	Corolla yellow or light yellow.		(4)
4 (3)	Herbs, mostly biennial; stems branched; leaves not convolute; anther appendages exserted; nutlets 4-5 mm		6 Onosma setosa
+	Subshrubs or perennial herbs; stems mostly not branched; leaves convolute; anthers included; nutlets 2.5-3 mm		7 Onosma simplicissimum
5 (2)	Corolla red, 7-9 mm, ca. as long as calyx lobes; filaments inserted ca. 2.5 mm above base of corolla tube		2 Onosma cingulatum
+	Corolla blue or red, 10-16 mm, longer than calyx lobes; filaments inserted 4-5.5 mm above base of corolla tube.		(6)
6 (5)	Stems several, branched at base; inflorescences terminal and axillary, capitate; corolla 1-1.2 cm		4 Onosma glomeratum
+	Stem single, unbranched, or branched at middle; inflorescences terminal, elongated; corolla 1.4-1.6 cm.		(7)
7 (6)	Plants gray; basal leaves oblanceolate, apex acuminate; inflorescences sometimes dichotomously branched; nutlets gray		3 Onosma mertensioides
+	Plants green; basal leaves linear-lanceolate, apex obtuse; inflorescences unbranched; nutlets yellow-white		5 Onosma zayuense
8 (1)	Anthers included, or only sterile apex exserted from corolla.		(9)
+	Anthers half to completely exserted from corolla.		(17)
9 (8)	Filaments and style pubescent.		(10)
+	Filaments and style glabrous.		(11)
10 (9)	Stems single, not branched; upper stem leaves hastate and usually clasping at base		11 Onosma paniculatum
+	Stems several, cespitose, branched from base; upper stem leaves cuneate or rounded at base		12 Onosma lijiangense
11 (9)	Corolla 2-2.7 cm.		(12)
+	Corolla 1-1.3 cm.		(14)
12 (11)	Corolla club-shaped, lobes apiculate; bracts longer than calyx		9 Onosma apiculatum
+	Corolla not club-shaped, lobes not apiculate; bracts not longer than calyx.		(13)
13 (12)	Leaves green, only 4-5 mm wide		8 Onosma irritans
+	Leaves gray-white, wider than 5 mm		10 Onosma gmelinii
14 (11)	Filaments not decurrent, base expanded, triangular		16 Onosma maaikangense
+	Filaments decurrent.		(15)
15 (14)	Filaments inserted near middle of corolla tube, decurrent part linear, mealy, minutely pubescent		15 Onosma waltonii
+	Filaments inserted at lower part of corolla tube, decurrent part oblong, not pubescent.		(16)
16 (15)	Leaf blade gray-white abaxially, densely strigose, with only midvein evident; corolla lobe short strigose inside on midveins		14 Onosma confertum
+	Leaf blade gray abaxially, densely pubescent and strigose, 3-veined; corolla lobes glabrous or nearly so		13 Onosma wardii
17 (8)	Filament bases and adjacent corolla tube pilose.		(18)
+	Filament base and adjacent corolla tube glabrous.		(21)
18 (17)	Filament insertion with sparse hairs, not forming a ring		17 Onosma liui
+	Filament insertion with dense hairs, forming a ring.		(19)
19 (18)	Stems herbaceous, pallid; stem leaves lanceolate, 3-8 × 1-1.5 cm, base rounded, apex acuminate, 3-veined, lateral veins conspicuous; corolla 10-ranked, minutely hispid inside		19 Onosma decastichum
+	Stems suffruticose, gray-green; stem leaves oblanceolate, 1-1.5 × 0.2-0.5 cm, base attenuate or subsessile, apex obtuse, only midvein evident.		(20)
20 (19)	Base of filaments and corolla interior glabrous; calyx ca. 6 mm; corolla 11-11.5 mm		21 Onosma farreri
+	Base of filaments and adjacent parts of corolla villous; calyx 7-9 mm; corolla 8-9.5 mm		20 Onosma sinicum
21 (17)	Stems single, stout, base 0.8-1.4 cm wide; plants biennial.		(22)
+	Stems usually several, more slender; plants perennial or, if biennial, cespitose.		(23)
22 (21)	Anthers half exserted; corolla 11-14 mm, throat 5-8.5 mm wide, tube glabrous inside		18 Onosma fistulosum
+	Anthers completely exserted; corolla 7-8 mm, throat 3-3.5 mm wide, tube sparsely pubescent inside		29 Onosma exsertum
23 (21)	Anthers and buds curved at apex		27 Onosma multiramosum
+	Anthers and buds straight.		(24)
24 (23)	Filament bases and adjacent corolla tube papillate, glandular.		(25)
+	Filament base and adjacent corolla tube not papillate or glandular, rarely papillate on decurrent part of filament.		(26)
25 (24)	Leaf blade lanceolate to oblong, only midvein evident; inflorescences terminal and axillary, branches slender; calyx lobes linear, 5-7 × < 1 mm; nutlets yellow-white, 2-3 mm, tuberculate, wrinkled		25 Onosma adenopus
+	Leaf blade ovate-lanceolate or linear-lanceolate, 3-veined; inflorescences terminal, branches stout; calyx lobes lanceolate, 7-9 × 1-2 mm; nutlets gray-brown, ca. 3 mm, papillate, tuberculate		26 Onosma nangqenense
26 (24)	Leaf blade gray-white abaxially, hispid, densely appressed pubescent.		(27)
+	Leaf blade green or light green abaxially, sparsely short appressed pubescent or pilose, sparsely hispid.		(28)
27 (26)	Leaves noticeably 3-veined; style glabrous		24 Onosma yajiangense
+	Leaves with only midvein evident; style pubescent below middle		23 Onosma album
28 (26)	Corolla obscurely pubescent outside, throat 4-9 mm wide; filaments decurrent, 6.5-7 mm		28 Onosma waddellii
+	Corolla short strigose outside, throat 4-5 mm wide; filaments not decurrent		22 Onosma luquanense