1 Flowers in a single, terminal glomerule (rarely also 1 at the next node down the stem); stamens exserted; leaves ovate to ovate-lanceolate, broadest near the rounded, truncate, or subcordate base, 1.5-3 (-4)× as long as wide.

..2 Leaves all sessile, or the best-developed with petioles < 5 mm long.

....3 Upper corolla lip about as long as the corolla tube

....3 Upper corolla lip about ½ as long as the corolla tube

..2 Leaves petiolate, the well-developed leaves with petioles (5-) 10-40 mm long.

......4 Corolla 30-45 mm long, scarlet-red, (3-) 4-8 mm broad at the expanded portion of the throat; [primarily of mountain seepages, streambanks, and boggy places]

......4 Corolla 14-35 (-36) mm long, white, lavender, or purple, 1-3 (-4) mm broad at the expanded portion of the throat; [of various habitats, usually dryish to mesic].

........5 Leaves deltoid-ovate to ovate, 2-6 cm wide, usually ca. 2× as long as wide; orifice of the calyx glabrous to slightly hirsute with a few long hairs; upper lip of the corolla 5-8 mm long and not bearded (M. clinopodia) or 13-16 mm long and slightly bearded (M. media) near its apex; outer surface of the corolla glabrous to evenly pubescent with short curled hairs.

..........6 Corolla white, greenish, or pale pink, the lower lip purple-spotted; outer bracts subtending the inflorescence green or pale (rarely with a purplish midvein); upper lip of the corolla 5-8 mm long, not bearded

..........6 Corolla deep purple, the lower lip usually not spotted; outer bracts subtending the inflorescence purple to red; upper lip of the corolla 13-16 mm long and slightly bearded near its apex

........5 Leaves narrowly-deltoid, ovate-lanceolate to lanceolate, 1-4 cm wide, usually ca. 3-4× as long as wide; orifice of the calyx densely hirsute with numerous erect, stiff, white hairs; upper lip of the corolla prominently bearded or merely pilose near its apex; outer surface of the corolla evenly pubescent with short curled hairs.

............ 7 Leaves glabrous; stem glabrous; upper lip of the corolla merely pilose near its apex

............ 7 Leaves canescent; stem variously hairy; upper lip of the corolla prominently bearded near its apex.

............ ..8 Corolla deep purple; middle lobe of the lower corolla lip 4-6 mm long; outer bracts subtending the inflorescence reddish

............ ..8 Corolla lavender, rose, or nearly white; middle lobe of the lower corolla lip 2-4 mm long; outer bracts subtending the inflorescence green (rarely the midvein only reddish).

............ ....9 Plants 10-40 cm tall; leaves subcoriaceous, glabrous or sparsely pubescent, dark green, shiny; calyx 5-8 mm long, the lobes conspicuously pustulate-glandular.

............ ......10 ; [of limestone glades and barrens of w. VA (Giles County) and e. WV]

............ ......10 ; [of rocky woodlands of the Ouachitas and nearby areas, AR and e. OK]

............ ....9 Plants 30-130 cm tall; leaves herbaceous, pubescent, light to medium green, matte (not shiny); calyx 7-11 mm long, the lobes not pustulate-glandular; [of various habitats].

............ ........11 Pubescence of the petioles and lower leaf surface hirsute or villous, the trichomes spreading, 1-3 mm long

............ ........11 Pubescence of the petioles and lower leaf surface canescent, the trichomes appressed (sometimes also with an admixture of longer, spreading trichomes)

1 Flowers in 2-6 glomerules, terminal and at 2-5 successive nodes down the stem; stamens included; leaves linear, lanceolate, to narrowly elliptic, usually broadest near the middle and tapered to a cuneate base, (2.5-) 3-8× (or more) as long as wide.

............ ..........12 Calyx lobes (3-) 5-10× as long as wide, the length including a spinose awn 2-7 mm long; corolla white to pink or lavender; inner bracts subtending the flowers 4-9 mm wide, abruptly acuminate into a spinose bristle

............ ............ 13 Bracts subtending the glomerules of flowers similar in shape, the outer bracts and inner bracts not strongly differentiated in width; corolla white to pink or lavender, with purple spots

............ ............ ..14 Calyx tubes 7-15 mm long; corolla tubes 11-18 mm long; [widespread in our region]

............ ............ ..14 Calyx tubes 5-7 mm long; corolla tubes 8-11 mm long; [s. and se. TX]

............ ............ 13 Bracts subtending the glomerules of flowers graduated in shape, the outer 2× or more as wide as the inner; corolla white to pink or lavender, usually without purple spots.

............ ............ ....15 Calyx tips stiff, 3-6 mm long, reddish or purplish; bracts elliptic, with veins strongly raised

............ ............ ....15 Calyx tips flexible, 1-3 mm long, greenish; bracts ovate, with veins only slightly raised

............ ..........12 Calyx lobes 1-3× as long as wide, narrowly to broadly triangular, acute or long-acuminate but not awned; corolla yellow, spotted with purple; inner bracts 8-14 mm wide, acuminate.

............ ............ ......16 Leaves linear or linear-lanceolate; [TX].

............ ............ ........17 Shrub, strongly and diffusely branched; leaves linear, ≤ 3 mm wide; stems and leaves canescent; petiole absent or minute, < 1 mm long

............ ............ ........17 Suffruticose; leaves linear-lanceolate to lanceolate, > 4 mm wide; stems and leaves green; petiole > 1 mm long.

............ ............ ..........18 Stems, petioles, and leaves densely pilose; calyx orifice glabrous; [s. coastal TX]

............ ............ ..........18 Stems, petioles, and leaves puberulent; calyx orifice pubescent; [sc. (inland) TX]

............ ............ ......16 Leaves lanceolate or ovate; [collectively widespread, including TX].

............ ............ ............ 19 Calyx orifice densely bearded by a cone of white trichomes; leaves broadly lanceolate; [c. TX]

............ ............ ............ 19 Calyx orifice glabrous or ciliate, not densely bearded; leaves lanceolate to ovate; [collectively widespread].

............ ............ ............ ..20 Calyx teeth broadly acute; calyx tube glabrous; flowers white to cream

............ ............ ............ ..20 Calyx teeth narrowly acute; calyx tube with scattered hairs between (and on) the veins; flowers yellow.

............ ............ ............ ....21 Midvein and/or laminar portion of lower leaf with longer, villous, multicellular hairs.

............ ............ ............ ......22 Leaves 2.2-3.5 cm long; upper bract tip acute; calyx lobe tips acuminate; {Atlantic Coastal Plain of ne. SC south to peninsular FL]

............ ............ ............ ......22 Leaves 3.2-10 cm long; upper bract tip acuminate; calyx lobes lanceolate; [collectively widespread inland and westwards].

............ ............ ............ ........23 Lower leaf surface pubescent primarily on and around midvein; calyx lobe face glabrous; lower corolla lip > 3.2 mm wide

............ ............ ............ ........23 Lower leaf surface pubescent throughout; calyx lobe face pubescent; lower corolla lip < 2.8 mm wide

............ ............ ............ ....21 Midvein and laminar portion of lower leaf with short, single-celled hairs or glabrous.

............ ............ ............ ..........24 Calyx lobes with outer surfaces and margins minutely hispidulous, lacking longer, spreading white hairs.

............ ............ ............ ............ 25 Leaves weakly veined; leaf veins with appressed or incurved hairs; [s. TX Coastal Plain and Tamaulipan Plain southwards]

............ ............ ............ ............ 25 Leaves strongly veined; leaf veins with mostly erect or ascending hairs; [widespread in our region]

............ ............ ............ ..........24 Calyx lobes with outer surfaces conspicuously pubescent with white spreading hairs 0.5-1.5 mm long.

............ ............ ............ ............ ..26 Leaf undersurface with appressed or incurved hairs 0.1-0.2 mm long, on the surfaces and the veins.

............ ............ ............ ............ ..26 Leaf undersurface with erect or ascending hairs 0.3-1.0 mm long, borne mainly or entirely restricted to the main veins