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1 Corolla strongly frontally flattened in life; flower 'throat' yellow; spur short, up to 3 mm long; stipules deeply pinnately lobed with few to many lateral segments, the terminal lobe resembling the leaf blades; leaf blades linear-lanceolate to elliptical, base cuneate to truncate; plants annual or biennial, without thickish rootstock; [of weedy habitats].
..2 Petals shorter than the sepals or scarcely surpassing them by 1-2 mm, cream-white (slightly yellowish); sepals nearly or fully concealing capsule
....3 Petals uniformly pale blue or cream-white, concolorous distally; terminal lobe of stipules with 0-3 crenations on each margin; quadrate stems recurved-puberulent or -hispidulous on face directly above a leaf node but essentially glabrous on the other faces; leaves all cauline
......4 Flowers < 1 cm long in profile; lower three petals cream-white, upper two purple-black at least in distal half; [occasional escape]
......4 Flowers > 1.5 cm long in profile; all petals variously colored, often with broad black border; [barely persistent following cultivation]
..........6 Foliage glabrous except for small scattered subappressed hairs on upper surface of leaf blades (especially near the margins), peduncles and stems glabrous; upper surface of leaf blades uniformly green; stipules weakly lacerate, with marginal processes < ¼ as long as the stipule; [moist loam of riverbanks and lawns, Appalachian, rare]
..........6 Foliage, peduncles and stems densely puberulent; upper surface of leaf blades silvery- to gray-green with darker green veins; stipules deeply laciniate with marginal processes > ½ as long as the stipule; [sandy loam, commonly on dolomite ledges in our range, e. WV, w. VA and c. OH to FL, AR and e. TX]
............ 7 Corolla white (rarely pale violet), spurred petal with extensive dense nectar-guide lines; spur short, 1–2 mm; cauline leaf blades broader than long, ovate- to deltate-reniform; stipules subentire or minutely toothed; [native of temperate eastern and tropical Asia, introduced to NJ and NY]
............ 7 Corolla cream-white, blue or purple, spurred petal with few fine inconspicuous nectar-guide lines; spur moderately short to elongate, 3–7 mm; cauline leaves longer than broad to broader than long but not deltate; stipules weakly to strongly lacerate or fimbriate; [native species, collectively widespread in our region].
............ ..8 Corolla wholly cream-colored; calyx ciliate; margins of leaf blades closely crenulate
............ ....9 Spur of basal petal 4-6 mm long; lateral petals bearded within; corolla uniformly blue
............ ....9 Spur of basal petal 10-15 mm long; lateral petals beardless; corolla pale violet with a purple-black eyespot surrounding the throat