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| 1 Herbage softly and densely white (to gray)-woolly; [rare escapes and persisting from cultivation]. |
| ..2 Perennial; leaf blades heavily lanate, narrowed to the base, the teeth (if any) concealed by the felt; calyx lobes concealed by tomentum |
| ..2 Biennial; leaf blades silky-pilose or tomentose, rounded to cordate at the base, obviously dentate; calyx lobes projecting beyond the pubescence |
| 1 Herbage variously pubescent or glabrous, but never white-woolly; [collectively common, both natives and aliens]. |
| ....3 Bracts of inflorescence (and upper leaves) mucronate (the mucros sometimes inconspicuous, appearing as short, whitish or blonde pointed spines, clearly differentiated from the blade); calyx lobes nearly as long as the tube; [extreme s. TX] |
| ....3 Bracts of inflorescence (and upper leaves) rounded to acute/pointed, not mucronate (or with mucros not clearly differentiated from the blade); calyx lobes, barious, mostly clearly shorter than the tube |
| ......4 Annuals from fibrous roots, typically freely branching from the base or from lower nodes; leaf blades 1-5 cm long, with rounded or obtuse apices (except acute to acuminate in S. annua); [aliens, except S. agraria]. |
| ........5 Leaves cuneate at base, acute to acuminate at tip; corolla 10-16 mm long (well exceeding the calyx); corolla mostly white, the lower lip yellow; upper corolla lip erect, the galea margin erose/crisped |
| ........5 Leaves cordate or truncate at base, rounded or obtuse at tip; corolla 4-9 mm long (barely or not exceeding the calyx); corolla white to pink, the lower lip not yellow; upper corolla lip straight, the galea margin entire. |
| ..........6 Calyx 3-5 mm long; corolla 4-6 mm long; [Gulf Coast (to Mexico) and scattered eastwards to FL and SC] |
| ..........6 Calyx 7-9 mm long; corolla 7-9 mm long; [rare waif, mostly from ballast] |
| ......4 Perennials from rhizomes, not branching in the lower portion (unless damaged); leaf blades often > 5 cm long, with acute apices; [natives, except S. floridana and S. palustris]. |
| ............ 7 Petioles (at least some of those of the principal stem leaves) > 1/5 as long as the blades. |
| ............ ..8 Calyx strongly glandular with atomiferous glands or gland-tipped hairs, or both. |
| ............ ....9 Calyx lobes narrowly lanceolate, about as long as the calyx tube; leaf blades lance-ovate to lanceolate, < 3 cm wide; stem angles glabrate to short retrorse pubescent; root tips with moniliform tubers; [native and weedy species, mostly of the Coastal Plain] |
| ............ ....9 Calyx lobes deltoid to deltoid-lanceolate, shorter than the calyx tube; leaf blades broadly cordate-ovate, usually > 3 cm wide; stem angles hispid; roots without tubers; [native species of rich mountain forests]. |
| ............ ......10 Calyx lobes aristate, with a linear tip 1-2 mm long. |
............ ........11 Stem faces eglandular; stem angles with spreading trichomes 1-3 mm long; leaves sparingly pubescent |
| ............ ........11 Stem faces copiously atomiferous glandular; stem angles with pustulate based spreading trichomes 1-3 mm long; leaves atomiferous-glandular mixed with sparse eglandular trichomes |
| ............ ......10 Calyx lobes angled or with linear portion < 1 mm long. |
| ............ ..........12 Calyx lobes deltoid; leaves broadly rounded with a cordate base and crenulate margins |
| ............ ..........12 Calyx lobes deltoid-lanceolate; leaves various. |
| ............ ..8 Calyx sparsely glandular or eglandular. |
| ............ ............ 13 Leaves ovate to broadly ovate, deeply cordate at base |
| ............ ............ 13 Leaves oblong, lanceolate, elliptic, or ovate-elliptic, not cordate or only slightly so. |
| ............ ............ ..14 Calyx hispidulous to strongly hispid with long, stiff, deflexed hairs; stem moderately to densely pubescent on the angles with hairs to 3 mm; leaves usually pubescent above (some forms glabrate); petioles rarely as much as 1-2 cm long |
| ............ ............ ..14 Calyx glabrous to moderately pubescent with short, soft hairs; stem glabrous to moderately pubescent on the angles; leaves sparsely pubescent or glabrate; petioles well developed (1-3 cm long), especially in shade forms. |
| ............ ............ ....15 Leaf blades ovate-oblong to elliptic; calyx lobes deltoid-acuminate to an apiculate tip, ½ to 2/3 as long as the calyx tube; bracts of the inflorescence usually conspicuous and only gradually reduced upward; plants generally more pubescent |
| ............ ............ ....15 Leaf blades oblanceolate, oblong, or narrowly elliptic; calyx lobes lanceolate, usually recurved-spreading in fruit, about as long as the calyx tube; bracts of the inflorescence inconspicuous, rapidly reduced upward; plants generally glabrate |
| ............ 7 Petioles < 1/5 as long as the blade or absent. |
| ............ ............ ......16 Stem below the inflorescence glabrous on the sides (rarely with a few remote hairs and/or glands) or atomiferous-glandular only. |
| ............ ............ ........17 Leaves linear-lanceolate to lanceolate or lance-elliptic, often widest below the middle, 3-15 (-20) mm wide; leaf margins entire to crenulate or serrulate. |
| ............ ............ ..........18 Leaf blades broader, 5-15 (-19) mm wide, the margins crenulate to finely serrate; herbage glabrate to hispidulous to strongly pubescent |
| ............ ............ ..........18 Leaf blades very narrow, 3-6 (-10) mm wide, the margins entire to obscurely crenulate; herbage glabrous to moderately pubescent |
| ............ ............ ........17 Leaves ovate-oblong to elliptic, usually widest near the middle, (1.6-) 2.0-5.0 (-6.0) cm wide; leaf margins crenate to sharply serrate. |
| ............ ............ ............ 19 Mature calyx lobes triangular deltoid and abruptly apiculate, less than half as long as the calyx tube. |
| ............ ............ ............ ..20 Leaf margins serrulate or serrate; stem nodes not bearded (sometimes obscurely fine-hairy); stem angles with scattered, pustulate, short deflexed hairs; [high-elevation montane habitats] |
| ............ ............ ............ ..20 Leaf margins crenulate or crenate; stem nodes bearded; lower stem angles copiously pubescent with 3-celled spreading hairs; [low-elevation Piedmont and Coastal Plain habitats] |
| ............ ............ ............ 19 Mature calyx lobes lanceolate or deltoid-acuminate to an apiculate tip, more than half as long as the calyx tube. |
| ............ ............ ............ ....21 Calyx sparsely to moderately pubescent with short, soft hairs; stem angles moderately pubescent to nearly glabrous; leaves sparsely pubescent or glabrate; principal leaves on petioles 1 to 3 cm long; bracts of the inflorescence usually conspicuous and only gradually reduced upward, the cilia ± incurved-ascending |
| ............ ............ ............ ....21 Calyx hispidulous to strongly hispid with long, stiff hairs; stem angles moderately to densely pubescent; leaves usually pubescent above (some forms glabrate); principal leaves usually subsessile, with very short petioles; bracts of the inflorescence usually inconspicuous and rapidly reduced upward; if conspicuous, bracts ciliate with long, stiffly spreading hairs. |
| ............ ............ ............ ......22 Calyx lobes flaring at maturity, conspicuously glandular with long stipitate trichomes and shorter sessile and subsessile glandular hairs; stem faces with occasional glandular and/or eglandular trichomes |
| ............ ............ ............ ......22 Calyx lobes straight at maturity, sparsely short glandular to eglandular; stem faces usually with a few atomiferous glands only |
| ............ ............ ......16 Stem below the inflorescence pubescent on the sides, as well as the angles. |
| ............ ............ ............ ........23 Calyx lobes lanceolate, acuminate, ½ or more as long as tube |
| ............ ............ ............ ..........24 Corolla purple-red; midstem leaf bases commonly shallowly cordate, nearly clasping |
| ............ ............ ............ ..........24 Corolla pink; midstem leaf bases rounded to broadly cuneate, hardly or not at all clasping. |
| ............ ............ ............ ............ 25 Calyx lobes lanceolate, more than half as long as the tube; flowers 6 per verticil; stem hairs prevailing soft and spreading, a short level commonly overtopped by a uniformly taller canopy layer; calyx with soft hairs |
| ............ ............ ............ ............ 25 Calyx lobes lanceolate to-subulate; stem hairs with at least some stiff, eglandular; calyx usually with some stiff hairs. |
| ............ ............ ............ ............ ..26 Fully open flowers with flaring/recurved calyx lobes; [w. VA, w. NC, extreme e. TN] |
| ............ ............ ............ ............ ..26 Fully open flowers with straight calyx lobes, scarcely flaring; [VA, KY, and MO northwards] |
| ............ ............ ............ ........23 Calyx lobes deltoid, no more than half as long as the calyx tube (but longer in S. alabamica); flowers 6-8 per verticil. |
| ............ ............ ............ ............ ....27 Leaf blades oblong/lanceolate; lowest leaves obtuse at apex; leaves < 3 cm broad, to 4 cm long; blades and stems velvety; corolla white; flowers 6 per verticil; [restricted to Santee River delta SC] |
| ............ ............ ............ ............ ....27 Leaf blades elliptic/ovate; lowest leaves acute at apex; leaves up to 5-8 cm broad, 8-18 (-20) cm long; corolla pink; flowers 6-10 per verticil; [absent from SC]. |
| ............ ............ ............ ............ ......28 Petioles of midstem leaves 10 mm long (or more); calyx lobes deltoid-lanceolate; stem and abaxial leaf surface sparingly to moderately glandular and with frequent soft eglandular hairs; [GA, TN, KY] |
| ............ ............ ............ ............ ......28 Petioles of midstem leaves to 6 mm long; calyx lobes strongly deltoid; stem and abaxial leaf surface abundantly to densely atomiferous glandular and with some stiff eglandular hairs. |
| ............ ............ ............ ............ ........29 Calyx campanulate; calyx lobe margins densely stipitate-glandular; [endemic of AL] |
| ............ ............ ............ ............ ..........30 Calyx 3.4-5 mm long, lobes about as long as tube; lobe margins with abundant coarse, glandular trichomes; pedicels 1 mm or more |
| ............ ............ ............ ............ ..........30 Calyx 5-6 mm long lobes less than ½ length of tube; lobe margins pubescent with eglandular trichomes, or a few glandular trichomes; pedicels to 0.5 mm long, rarely longer |
| ............ ............ ............ ............ ........29 Calyx tubular/cylindric; lower leaf surface densely atomiferous or not; calyx lobe margins pubescent, but not densely stipitate-glandular. |
| ............ ............ ............ ............ ............ 31 Leaf blades ovate, margins crenate; lower leaf surface glandular, not densely so; [NC, VA, WV, MD] |
| ............ ............ ............ ............ ............ 31 Leaf blades lanceolate- ovate lanceolate, commonly lyrate toward base; margins serrated; lower leaf densely atomiferous glandular; [AR, OK] |