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1 Leaves densely white tomentose below (felty white, the surface obscured or nearly so); corolla blue; petioles of median leaves 10-15 (-20) mm long; calyx tube 5-7 mm long at flowering; [cultivated as an ornamental and rarely naturalized]
..2 Corolla yellow or greenish-yellow; calyx lobes obtuse or subacute, 1-1.5 mm long at anthesis; calyx lobes and bracts green; midstem internodes glabrous or minutely pubescent; lower surface of the leaf pubescent on the veins and surface
....3 Corolla tubes 7-8 (-10) mm long; leaf bases subcordate to rounded; leaf blades 6-8 (-12) cm long, 4-6 cm wide, averaging about 1.5× as long as wide; [alien, rarely naturalized]
....3 Corolla tubes 6-7 mm long; leaf bases rounded to subcordate; leaf blades 8-15 cm long, 3.5-7 cm wide, averaging about 2× as long as wide; [native]