Coefficient of Conservatism:
Coefficient of Wetness:
P. capillaceus of Michigan Flora.
Shallow areas in soft water lakes and ponds in the southwestern Lower Peninsula. A primarily coastal species, local inland.
The peduncled dense cylindric spikes arising from axils of floating leaves are most conspicuous; though small nearly spherical spikes on slightly longer recurved peduncles also occur in the axils of submersed leaves. This is an extremely delicate species with long, narrow submersed leaves only ca. 0.1–0.3 mm wide and usually 200–500 times as long as wide. The very similar P. diversifolius is known from northern Indiana and Ohio, and could occur in southern Michigan. It has broader submersed leaves, mostly about 0.5 mm wide and usually much less than 200 times as long as wide.