Coefficient of Conservatism:
Coefficient of Wetness:
Wet sandy or muddy shores and ditches, especially in springy places; in flowing water of streams and rivers as well as on their banks; rarely on floating mats in peatlands.
Following a number of recent authors who do not distinguish American from Old World plants of this species, we include here V. catenata Pennell, often applied to the American element (to which also the names V. comosa and V. salina have sometimes been misapplied). The typical Old World element was collected in 1936 in Keweenaw Co. (F. J. Hermann 7998, MICH, GH). It differs in more erect-ascending pedicels, relatively narrower sepals, and capsules a bit narrower than long.
This is quite a variable species. Most of our specimens are ± glandular-pubescent in the raceme and on the upper part of the stem (var. glandulosa Farw.) The lower leaves and leaves on basal offshoots sometimes are short-petioled. Rarely plants have alternate racemes, as in V. scutellata. Submersed plants (especially in flowing water) frequently have very limp and rather elongate aquatic leaves; these are opposite so such plants ought not be confused with a Potamogeton, which they might otherwise resemble.