Coefficient of Conservatism:
Coefficient of Wetness:
All Michigan populations seen have been completely submersed or at the edge of the water in small lakes with sandy or sandy-mucky bottoms. Often locally abundant, forming small moss-like mats in shallow water (up to 6 dm).
An easily overlooked little plant, at most a few cm tall, with tiny opposite rounded leaves, and likely to be mistaken for, perhaps, seedling Hypericum, until one notices the axillary fruit. The carpels are usually 2 in this species, and the seeds have rows of round-ended (rather than angled) pits.