Infrequent to frequent in the lake area with two stations south of it. It prefers the dried-up borders of ponds that are well covered with old leaves. While it sometimes grows in marshes and in muck it prefers to root in decaying vegetation.

Rhizomatous perennial, glabrous throughout, or occasionally hairy; stems erect or ascending, 1-4 dm; lvs all opposite, sessile, linear to lanceolate, 2-8 cm נ2-15 mm, (3-)4-20 times as long as wide, entire or with a few remote, divergent, slender small teeth; racemes axillary, pedunculate, mostly 5-20-fld, the pedicels becoming 6-17 mm; cor bluish, 6-10 mm wide; fr flattened, 2.5-4 mm, evidently wider than high, conspicuously and rather broadly notched; style 2-4 mm; seeds 5-9 per locule, 1.2-1.8 mm; 2n=18. Swamps and bogs; Eurasia and the n. two- thirds of the temperate zone in N. Amer., blanketing our range. May-Sept.

Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.

©The New York Botanical Garden. All rights reserved. Used by permission.