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..2 Perennial with stoloniferous rhizomes, rooting at lower nodes; stems 20-30 (-40) cm tall; corolla 11-16 mm long
..2 Annual with fibrous roots; stems < 20 cm tall; corolla (4-) 5-10 mm long
....3 Fruiting calyces closed at the throat, lower lobes turned upward against the upper lobe
......4 Flowers herkogamous, corolla limb expanded 10–15 mm (pressed)
........5 Fruiting calyces minutely hirtellous; stems often prostrate to decumbent but becoming fully erect at least in the inflorescence, commonly distinctly fistulose
........5 Fruiting calyces glabrous to sparsely villous-glandular; stems prostrate to erect, not fistulose