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1 Plant a rhizomatous aquatic; leaves spatulate, entire, 10-20 mm long and 0.3-2 mm wide (reminiscent of Limosella or Lilaeopsis)
..2 Inflorescence of a solitary, terminal flower; bracteal leaves alternate
....3 Inflorescence of terminal and axillary spikes; flowers 6-8 mm long
......4 Corolla yellow; stem viscid glandular-pubescent; plant usually 2-4 dm tall
......4 Corolla blue; stem glabrous; plant usually 3-15 dm tall