Flower:

Compact clusters of stalked flowers at the top of the stem and arising from upper leaf axils, the clusters at the tips of long, slender stalks covered in sticky hairs. Flowers are blue to violet, about 2/3 inch wide, bell shaped with 5 spreading lance to egg-shaped petals that are a bit ruffled around the edges and are longer than the floral tube. The throat of the tube is creamy white with dark lines; extending well out from the center is a single white style with a 3-parted stigma at the tip, the tips purple or edged with purple, and 5 pale-tipped, white stamens that are shorter than the style.

The calyx surrounding the base of the flower has 5 lance-oblong lobes that are 3 to 4 times longer than the calyx tube, the outer surface and flower stalk are covered with spreading, sticky hairs.

Leaves and stems:

Most leaves are not associated with a flowering stem but emerge nearby from short stems on underground rhizomes. These leaves and the lowest stem leaves are pinnately compound with 3 to 27 leaflets, up to 6 inches long with a long stalk. Stalks have narrow edging and may appear grooved. Leaflets are lance-linear, ½ to 1½ inches long, toothless and hairless.

Stem leaves are few, alternate, becoming smaller with shorter stalks as they ascend. Flowering stems are long and rather slender, mostly smooth in the lower plant but with dense, sticky hairs towards the tip and on the cluster and flower stalks.

Fruit:

Fruit is a small capsule containing up to 10 tiny, dark brown seeds.

Notes:

Polemonium lacustre was previously considered a subspecies of Polemonium occidentale (subsp. lacustre), but recent genetic testing found it to be distinct enough from the more common subsp. occidentalis of the Rocky Mountains to warrant being split into a separate species. It requires wet swamps associated with white cedar, black spruce and tamarack. In spite of nearly 50 years of extensive survey of what appears to be similar habitat throughout the upper Great Lakes, it is severely restricted to just a handful of locations. According to the DNR, it was first discovered in Minnesota in 1944 and today is currently known from just a handful of separate populations in two Minnesota counties plus one county in Wisconsin. In both states it is ranked as Critically Imperiled and so listed as Endangered, though it is not presently Federally listed.