Basis for Listing

In Minnesota, wild populations of Hydrastis canadensis are currently known only in Dodge, Fillmore, Olmsted, Rice, and Winona counties. It is possible that undiscovered populations occur in Houston and Wabasha counties. There may also be small, cultivated plots or artificially "woods grown" colonies in other southeastern counties. It is clear that H. canadensis has always been rare in Minnesota, in part because southeastern Minnesota is at the northwestern periphery of its North American range. Recently, however, it has become even rarer, not only in Minnesota, but across its entire range because of intensive and unsustainable exploitation by commercial root diggers.

Hydrastis canadensis has significant monetary value in the pharmacological trade, and "wildcrafting" has a distinct appeal to many people. Hard data on harvest activity in Minnesota is not available, but anecdotal evidence indicates that it does occur. Therefore, the main threat to H. canadensis may be the selective exploitation of the plant itself rather than loss of its habitat. Even though illicit root digging is a threat, H. canadensis has also experienced a reduction of suitable habitat through residential and road construction, heavy grazing, unsustainable logging, and land clearing for agriculture. However, because of its market value, habitat preservation alone will not secure this species in Minnesota. Hydrastis canadensis was listed as a state endangered species in 1984.

  Description

Fertile plants have 1 stem and 2 palmately lobed leaves rising from a yellow rhizome that is thick and knotted. The single flower is inconspicuous and appears for only a short time in early spring. It is terminal, with 3 sepals, no petals, and 12 or more pistils. Flowers develop into a head of crimson, raspberry-like 2-seeded berries.

  Habitat

Hydrastis canadensis occurs in mesic hardwood forests, usually in sheltered ravines or on talus slopes. It appears to be intolerant of grazing or disturbances that open the forest canopy. It is often associated with a rich woodland ground cover of Asarum canadense (wild ginger), Hepatica acutiloba (hepatica) and Caulophyllum thalictroides (blue cohosh). Populations range from just a few scattered individuals to more than 100 at each site.

  Biology / Life History

Plants produce insect-pollinated flowers in the spring before the canopy trees leaf out. Fruits are formed in late spring-early summer. The rhizome can be several inches long, but grows at a rate of perhaps 2.5 cm (1 in.) per year. Over time the rhizome may fragment and produce a second plant. However, most reproduction is accomplished by seeds. This is a long-lived perennial species adapted to shady habitats and moist soils.

The best time to search for H. canadensis is when leaves are fully expanded from May to August.

  Conservation / Management

A decrease in undisturbed, deciduous woodlands and steady pressure from root diggers has contributed to a decline of H. canadensis throughout its range (Ford 1993). Root diggers may still be actively seeking this plant in Minnesota, subjecting remaining populations to harvest pressure. Any such harvest is illegal because the endangered species law prohibits the taking of wild H. canadensis for any purpose without a permit from the DNR. Major canopy removal or silvicultural treatments that disturb the soil should be avoided near H. canadensis populations.

  Conservation Efforts in Minnesota

Several H. canadensis populations occur on State Park, county park, Wildlife Management Area, and State Forest lands. Unfortunately, it is even difficult to protect plants on public land from illegal harvest.

  References and Additional Information

Charette, L. A. 1964. Hydrastis canadensis in New England. Rhodora 66:94-95.

Ford, B. A. 1997. Hydrastis. Pages 87-88 in Flora of North American Editorial Committee, editors. Flora of North America north of Mexico. Volume 3. Oxford University Press, New York, New York.

Nekola, J. C. 1990. Rare Iowa plant notes from the R. V. Drexler Herbarium. Journal of the Iowa Academy of Sciences 97(1):55-73.

Ownbey, G. B., and T. Morley. 1991. Vascular plants of Minnesota: a checklist and atlas. University of Minnesota Press, Minneapolis, Minnesota. 320 pp.

Rosendahl, C. O., and J. W. Moore. 1947. A new variety of Sedum rosea from southeastern Minnesota and additional notes on the flora of the region. Rhodora 49:197-202.