Coefficient of Conservatism:
Coefficient of Wetness:
R. W. Smith
An irregularly circumpolar species, ranging west in North America only to Lake Michigan and northern Ontario. Wet gravelly, rocky, or sandy shores and banks; moist ground, meadows, swampy hollows.
This is a rather showy species, thanks to the numerous white flowers. Not only does it have more flowers in each ultimate cyme (distal to a bract), but there is also usually more than one such ultimate cyme at the end of a stem or branch, so the impression is of many more flowers in a terminal inflorescence than are seen in other similar species (only G. labradoricum and G. obtusum have flowers as large as in G. palustre). The pedicels at maturity are ± strongly divergent, a pattern evident even before the fruit begins to ripen. In G. obtusum and other species, the pedicels may be divergent as the fruit nears maturity, but usually they are ± ascending. The leaves in G. palustre are generally 5–6 in well-developed whorls, with margins spreading- or antrorse-scabrous.