Comments: Polemonium vanbruntiae occurs from New Brunswick and Quebec south to Maryland and West Virginia. It is nowhere common, but seems to be more abundant in New York state than anywhere else in its range. Approximately 19 current populations are known in West Virginia, totaling over 20,000 stems. In Maryland, approximately 9 populations total over 10,000 stems. The plant was known from a single historical site in New Jersey, and is presumed extirpated from that state. At least five historical populations were known in Pennsylvania; one of these was extant in 1986. One of the Pennsylvania populations (in the western part of the state) is known to have been destroyed by flooding. In New York, approximately 22 contemporary localities total over 50,000 stems. There are an additional 20 historical localities in New York. In Vermont, 5 small populations total over 1300 stems. Maine has a single known population, with fewer than 10 plants. Two contemporary and one historical population are known from the eastern townships in Quebec, but current field data are lacking (Lavoie 1991). A single population is known from New Brunswick, but it is not confirmed to be native (Hinds 1986).
Polemonium vanbruntiae is found in a variety of wetland habitats, including hardwood and softwood swamps, shrub swamps, marshes, bogs, lakeshores, woodland swales and seeps, spring runs, and wet roadsides, mostly at higher elevations (at least in the southern part of the plant's range). The Maryland populations (all in the western, mountainous part of the state) are at elevations between 2300 and 2700 feet. West Virginia populations are mostly at elevations of 2000-4000 feet. Elevations of New York populations range from 1190 to 3870 feet, with most of the populations between 1200 and 2500 feet. In Vermont, elevations range from approximately 350 to 1800 feet. It may be that elevations generally decrease with increasing latitude, but elevations of the Quebec and New Brunswick populations are not available to corroborate this.
It appears that this plant has a rather wide ecological tolerance; it is found in a variety of wetland types. Its rarity can probably not, therefore, be attributed to habitat scarcity. However, very little work has been done to actually quantify the habitat characteristics in successful or vigorous populations of this plant. Conversations with biologists familiar with the species point to some common features of habitats throughout its range: seepage water is a common (though not constant) feature; water is usually not standing above the surface for any significant period during the growing season (flooding seems to cause mortality); and open or partially open wetlands have the largest and most vigorous populations (the plant occurs in shaded sites, but populations tend to be small).
Ed Thompson (1990) and others have measured water pH at several populations in Maryland, finding pH levels of 6.6-6.7. Thompson describes the apparent ideal habitat as open areas influenced by circumneutral springs. He further proposes that the plant's pH range tolerance is rather narrow. Bartgis (1991) notes that most of the Maryland and West Virginia populations are associated with the Greenbrier limestone (the only major limestone formation in that area).
Associated plants listed by recent inventory workers attest to the wide variety of wetland habitats in which this species may be found. Many of these species are generalists, occurring in many kinds of wetlands; others are more habitat-specific. Associates include: Acer rubrum, Alnus incana, Carex stricta, Osmunda regalis, Osmunda cinnamomea, Crataegus SPP., Cornus SPP., VIBURNUM SPP., Saxifraga pensylvanica, Carex bromoides, Glyceria canadensis, Viburnum recognitum, Calamagrostis canadensis, Phalaris arundinacea, Equisetum sylvaticum, Senecio aureus, Urtica dioica, Salix SPP., Larix laricina, Thuja occidentalis, Ribes hirtellum, Platanthera dilatata, Aconitum noveboracense, Ilex verticillata, Prunella vulgaris, Scirpus SPP., Carex SPP., Vicia cracca, Onoclea sensibilis, Spiraea latifolia, PLATANTHERA FIMBRIATA, Iris versicolor, Mimulus ringens, Eriophorum SP., Sphagnum SPP., Drosera rotundifolia, Picea mariana, CIRCIUM MUTICUM, Spiranthes SP., Abies balsamea, Tsuga canadensis, Picea rubens, BETULA ALLEGHENIENSIS, Fraxinus nigra, Rhus vernix, Thalictrum polygamum, Impatiens capensis, Cinna latifolia, Carex leptalea and Carex crinita.
Careful descriptive work is needed before any conclusions can be drawn about the habitat requirements of this species range-wide.