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3 Young stems densely white-hairy; leaf undersurfaces white-hairy; corollas cream-white, with pale yellow pleats and with maroon markings in the tube, 2.5-3 cm long
4Corollassalverform, the long narrow tube cylindrical (with sides more-or-less parallel) for most of its length, the limb abruptly flaring at the summit of the tube.
5Corollas 3-15 cm long, predominantly lavender to white; flowers open from evening until early morning.
6 Leaves tomentose beneath; corolla mostly white on the outer surface, lavender to purple on the inner surface, thus bicoloredin-and-out; [of outer Coastal Plain dunes, hammocks, and shell middens from se. NC southward]
6 Leaves glabrous (or with scattered hairs or large fleshy hairlike structures) beneath; corolla either white on both surfaces or lavender on both surfaces, not bicoloredin-and-out; [weedy, widespread, of disturbed habitats].
4Corollasfunnelform, the short to long tube expanding in diameter upwards from below the middle, the limb gradually to abruptly flaring at the summit of the tube.
18Sepals < 2 cm long at anthesis, abruptly narrowed upwards, the long subacute tips strongly spreading or recurved outwards; corolla < 3.5 cm long; peduncles very short.
18Sepals ca. 3 cm long at anthesis, gradually narrowed upwards, the long acute tips suberect, straight, scarcely spreading; corolla 4-4.5 cm long; peduncles long or short
15Pedicels and pedunclesglabrous or with short, appressedtrichomes; gynoecium 2-parted; sepals 4-15 mm long; corollas mainly pink, lavender, or white, the tube and throat mainly deeper pink, purple, or maroon (but some species – I. tricolor, I. aristolochiifolia -- blue with white or yellow throats).
19 Leaves palmately, pinnately, or pedately compound or pseudocompound (so deeply parted as to appear superficially compound).
20 Leaves pedately compound, the leaflets or segments 1.5-3 mm wide; corollas 1-1.2 cm long, white; [TX]
24Corollas white with a white or purple throat (I. aquatica) or yellow or purple throat (I. imperati); larger leaves either hastate (I. aquatica) or 3-7-lobed (I. imperati).
35Corollas 2-4.5 cm long, 2.2-3.2 cm in diameter across the limb, at least partly pink to lavender (or entirely white in I. batatas); seeds shortly pubescent on the angles.
36Sepals more-or-less equal in length, oblong-lanceolate, with acuminateapices; leaves 2-5 cm wide; [native, widespread in the southern portion of our region, especially in the Coastal Plain].