1	Middle lobe of lower corolla lip narrow, ligulate; upper corolla lip always purple-red or brown.		(2)
+	Middle lobe of lower lip of corolla circular to ovate or obovate; upper corolla lip yellow (yellow and purple-red in M. delavayi).		(5)
2 (1)	Dichotomous cymes 2- or 3-flowered, axillary		2 Microtoena pauciflora
+	Dichotomous cymes many flowered, axillary or in terminal panicles.		(3)
3 (2)	Leaf base broadly truncate-cuneate, decurrent into winged petiole 5. M. insuavis		5 Microtoena insuavis
+	Leaf base cordate.		(4)
4 (3)	Calyx ca. 3 mm; leaves triangular-ovate, rarely oblong-ovate; stem spreading villous, retrorsely minutely tomentose		1 Microtoena patchoulii
+	Calyx 6.5 mm; leaves ovate-cordate; stem sparsely glandular villous, spreading hispid		3 Microtoena mollis
5 (1)	Cymes ± sessile, in terminal ± spicate panicles		4 Microtoena subspicata
+	Cymes pedunculate and/or axillary, not in terminal ± spicate panicle.		(6)
6 (5)	Calyx teeth triangular-subulate, apex slightly curved or hooked.		(7)
+	Calyx teeth triangular to linear, if triangular-subulate and apically slightly curved, then posterior tooth linear, long.		(11)
7 (6)	Posterior tooth of calyx ca. 2 × as long as other teeth		16 Microtoena urticifolia
+	Calyx teeth subequal, or posterior tooth only slightly longer.		(8)
8 (7)	Panicle compact; calyx glabrous except for ciliolate margins		18 Microtoena prainiana
+	Panicle lax; calyx glandular hairy.		(9)
9 (8)	Leaves subglabrous except sometimes for veins; calyx broadly campanulate, finely glandular puberulent outside		20 Microtoena megacalyx
+	Leaves hairy; calyx campanulate.		(10)
10 (9)	Leaves ovate-cordate to triangular-ovate, adaxially finely strigose, abaxially densely appressed tawny hispidulous along veins		17 Microtoena moupinensis
+	Leaves oblong-ovate, adaxially sparsely minutely hispid, abaxially spreading hispid along veins		19 Microtoena longisepala
11 (6)	Posterior calyx tooth 2.5-3 × as long as other teeth, anterior 4 teeth minute, narrowly triangular to triangular-subulate, equal.		(12)
+	Posterior calyx tooth up to 2 × as long as anterior teeth.		(13)
12 (11)	Stems, petioles, and abaxial leaf surface densely hairy; cymes in short compact panicles; posterior calyx tooth linear, ca. 3 × as long as other teeth; upper corolla lip not auriculate		13 Microtoena miyiensis
+	Stem, petioles, and abaxial leaf surfaces sparsely hairy; cymes in elongated loose panicles; posterior calyx tooth lanceolate ca. 2.5 × as long as other teeth; upper corolla lip basally ligulate-auriculate		12 Microtoena maireana
13 (11)	Calyx teeth lanceolate to linear-lanceolate.		(14)
+	Calyx teeth triangular-lanceolate, triangular, or oblong.		(17)
14 (13)	Cymes 1-3-flowered, axillary.		(15)
+	Cymes many flowered, in terminal panicles though sometimes also axillary.		(16)
15 (14)	Cymes 2- or 3-flowered; peduncle 3-5 mm		11 Microtoena albescens
+	Cymes 1-flowered; peduncle 6-15 mm		10 Microtoena affinis
16 (14)	Upper corolla lip often purple-red (yellow in var. lutea); terminal panicles ca. 2-3 × 3-41 cm		6 Microtoena delavayi
+	Corolla uniformly yellow; terminal panicles 4.5-13 × ca. 3.5 cm		9 Microtoena stenocalyx
17 (13)	Calyx teeth only slightly unequal, posterior tooth longer, oblong, apex subacute		14 Microtoena robusta
+	Calyx teeth obviously unequal, posterior tooth much longer, triangular-ovate to triangular-lanceolate.		(18)
18 (17)	Calyx teeth triangular-ovate; panicle of 3(-5)-flowered cymes, terminal on lateral branches, or a few cymes solitary, nearly apical		15 Microtoena vanchingshanensis
+	Calyx teeth triangular-lanceolate; inflorescences not as above.		(19)
19 (18)	Cymes axillary and terminal, lax, branches 1-sided; at least some peduncles over 2 cm; bracts reduced, minute, or absent		7 Microtoena muliensis
+	Cymes all dichotomous, axillary; peduncles (1-)1.6 cm; bracts lanceolate, 2-3 mm		8 Microtoena omeiensis