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..2 Flowers opening in morning; floral tubes 5-25 (-33) mm long, the upper half or more funnelform; plants glandular-puberulent.
....3 Leaf base clasping, truncate or subcordate; plants densely pubescent with a mixture of hairs, short-pilose and often hirtellous, sometimes also strigillose and glandular-puberulent in the inflorescence
......4 Plants glabrous throughout, or sometimes glandular-puberulent in inflorescence; blades linear to oblanceolate or lanceolate, magins entire to subentire, rarely undulate
......4 Plants sparsely strigillose, sometimes also glandular-puberulent in inflorescence; blades mostly oblanceolate or lanceolate, margins serrulate to subentire, undulate
..........6 Pubescence densely and finely strigillose; leaves linear to narrowly lanceolate or oblanceolate, 1-9 cm long, margins subentire to spinulose-serrate (if coarsely spinulose-serrate, longer than 3.5 cm); [widespread in the Great Plains]
..........6 Pubescence rather sparse, hairs stout; leaves mostly oblanceolate, 1.5-3.5cm long, margins coarsely spinulose-serrate; [dunes, sandy soil; endemic to se. TX, mostly along the coast]
............ 7 Plants perennial from a woody rootstock, stems several to many, erect to decumbent, 1-4 dm tall or long; leaves 1-4 cm long; [TX westward]
............ 7 Plants annuals or short-lived perennials, stems one to several, erect, 3-8 dm tall; leaves 2.5-9 cm long; [disjunct eastward as far as AL in calcareous substrates].