Coefficient of Conservatism:
Coefficient of Wetness:
A circumpolar species, usually of alkaline waters: interdunal pools and wet flats, fens, marshes, ponds, rivers, lakes; may grow in water a meter or more deep, but thrives and flowers in shallow water.
The lower lip of the corolla is relatively flat (except at the base) compared with the lower lip in U. vulgaris, which has the sides turned down, giving it a strongly humped aspect. The spur in U. vulgaris is more conical (broad-based) and curved less strongly under the lip; the more slender spur in U. intermedia is ± closely pressed to the bottom of the lip, even into a concavity. These two common species, often growing together, can thus be easily identified without close examination when in bloom.
The bladders in U. intermedia are as long as 5 mm on some individuals, though usually they are 1–3.5 mm. In shallow water (or very recently exposed wet mud) the green leaves when dense often give a mossy appearance (though actually flat and fan-shaped in outline), while the bladder-bearing branches are buried in the substrate.
The mysterious U. ochroleuca R. W. Hartm. has been collected near the north shore of Lake Superior in Ontario, and may occur in Michigan. It has a spur about half the length of the lower lip; in U. intermedia it is about as long. The specimen could also be the even less well known U. stygia G. Thor.