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Phacelia franklinii (R. Br.) Gray
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Basis for Listing
A total of nine records of Phacelia franklinii have been found in Minnesota. Five of the nine records date prior to 1951 and they have not been able to be relocated. The four recent records are quite small and consist of only about 20 plants in total. Since this is a relatively large and conspicuous plant, it is unlikely that it has been overlooked during surveys. Thus, it seems safe to conclude that this is a very rare species. Exactly why it is so rare is not known. Phacelia franklinii was listed as a special concern species in Minnesota in 1996, however, elevating its status to threatened is currently being considered.
Phacelia franklinii is the only member of its genus to occur in Minnesota. It has stems that grow to about 60 cm (2.0 ft.) tall. The leaves are pinnately parted with many lanceolate or oblong-linear lobes that are often cut-toothed. The flowers are bluish to white, subsessile, and arranged in a hairy, short, dense spiraled raceme.
The Minnesota records of P. franklinii are from a number of slightly different habitat types near lakes including cliffs, talus, tip-up mounds, and rocks. All of these are considered early successional, sparsely vegetated habitats, which corresponds with the species apparent need for small patches of disturbance. They are characterized by annual, biennial, or short-lived perennial plant species. If searching for this species, it might be wise to also consider lakeshores and riverbanks as potential habitat.
Biology / Life History
As is typical for annual or biennial species, P. franklinii requires narrow ecotones or small patches of disturbance where there is direct sunlight and little root competition. Such disturbances are often caused by a single tree tipping over or a single boulder falling from a cliff. They do not have to be large areas of disturbance caused by storms, fire, insect infestation, or logging. A stable, late successional forest community of the type that occurs in northeastern Minnesota appears to offer enough of these small disturbance habitats for a metapopulation of P. franklinii. Forest fires may also play a role in habitat creation and maintenance, but that possibility has not yet been demonstrated.
Conservation / Management
Large scale disturbances such as clearcutting or mining do not appear to be appropriate for P. franklinii and may have the opposite effect of eliminating the greater habitat in which the species' microhabitat occurs. Invasive species including Centaurea maculosa (spotted knapweed) and several non-native Hieracium spp. (hawkweeds) are also becoming more abundant in P. franklinii habitat, which may pose a serious risk to the long-term viability of the remaining populations. There is very little that can be done in terms of active management for P. franklinii, but if large landscape mosaics are maintained in a relatively natural condition, the species should be able to find habitat and sustain itself.
Conservation Efforts in Minnesota
Most of the habitat of P. franklinii is within the Superior National Forest. That fact, in itself, does not denote any active conservation effort; however, it does open the possibility for future conservation actions.
Butters, F. K., and E. C. Abbe. 1953. A floristic study of Cook County, northeastern Minnesota. Rhodora 55:21-201.
Gillett, G. W. 1960. A systematic treatment of the Phalelia franklinii group. Rhodora 62:205-22.
Judziewicz, E. J. 1997. Franklin's phacelia (Phacelia franklinii (R. Br.) A. Gray) (Hydrophyllaceae) on Isle Royale (Michigan) and in the Lake Superior region. Michigan Botanist. 36:73-77.
Lakela, O. 1965. A flora of northeastern Minnesota. University of Minnesota Press, Minneapolis, Minnesota. 541 pp.
Penskar, M. R. 2008. Special plant abstract for Phacelia franklinii (Franklin's phacelia). Michigan Natural Features Inventory, Lansing, Michigan.