CPC National Collection Plant Profile

Pedicularis furbishiae

Jean Baxter

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CPC National Collection Plant Profile

Pedicularis furbishiae

Common Names: 
Furbish lousewort, Furbish's wood betony
S. Wats.
Growth Habit: 
CPC Number: 


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 Fish & WildLife

Pedicularis furbishiaeenlarge
Photographer: Jean Baxter
Image Owner: New England Wildflower Society

Pedicularis furbishiae is Fully Sponsored
Primary custodian for this plant in the CPC National Collection of Endangered Plants is: 
Elizabeth J. Farnsworth contributed to this Plant Profile.

Pedicularis furbishiae

Pedicularis furbishiae is a narrow endemic, found only along 225 km of the pristine St. John River system of Maine and adjacent New Brunswick. Kate Furbish, botanist and wildflower artist, discovered the plant in 1880, and it has been intensively studied ever since. One of the first plants to receive concerted conservation attention in North America in the 1970's, Pedicularis furbishiae is a poster-child for conservation biology, and an exemplary case study for understanding the complex phenomena associated with metapopulations. A string of ephemeral sub-populations (demes) establish along the river's edge and persist for a short time before ice-scouring by the wild river destroys them and hurries their seeds downstream, where the plants re-establish and begin the cycle again. The future is precarious for Pedicularis furbishiae; river dams, climatic change, increasing run-off, pollutants, recreationists, and invasive species all can impact its fragile riverine habitat. Only a highly coordinated, international strategy can protect the St. John watershed and the large-scale natural processes that shape the community of Pedicularis furbishiae and many other rare species. Ambitious efforts are underway.

Plant Description:
Pedicularis furbishiae is an herbaceous perennial. Its distinctive, deeply lobed, toothed, and hairy leaves (4 to 20 cm long) grow in a basal rosette. In late July and August, reproductive plants send up a flowering spike (scape) up to 1 m tall, with a cluster of tubular, yellow flowers 2 cm long, each subtended by a stout bract. The fruits are oval capsules with small (2mm long), gray seeds.

Distribution & Occurrence

State Range
State Range of  Pedicularis furbishiae
  Pedicularis furbishiae grows mainly on north- or northwest-facing, narrow strips of steeply sloping river banks, usually associated with groundwater seeps in relatively circumneutral, gravelly soil left by glaciers (USFWS 1991, Maine Department of Conservation 1999, COSEWIC 2001). These riverside areas are frequently scoured and eroded during the ice break-up of the spring melt (which is a spectacle on the St. John River, due to its unique geomorphology [Kite 1983]), and may be denuded of vegetation in places. The climate is continental and cold, with long winters and short growing seasons (USFWS 1991).

On the New Brunswick side of the river, the plant grows in three distinct areas: 1) the first on gravelly calcareous soil about 8 m away from the water's edge, at the shade line of the forest; 2) the second in a more sunny, eroded bank strewn with cobbles; and 3) on the east bank of a shady railroad cut more than 400 m from the river's edge in drier, sand and gravel soils (COSEWIC 2001). In Maine, plants are found in about a dozen or more sub-populations (variable from year to year) clustered mainly along the river's edge. Systematic ecological surveys have revealed that Pedicularis furbishiae is associated with riverbank areas that have typically suffered ice scour within the past 3 to 10 years, and are steeper, wetter, and characterized by high species richness relative to areas not supporting the taxon (Gawler 1988, Menges 1990).

Plant species associated with Pedicularis furbishiae include a variety of riverside taxa commonly associated with northern (or western) rivers with rich bedrock, as well as several rare species: Alnus spp., Anemone canadense, Arnica mollis, Aster spp., Astragalus alpinus var. brunetianus, Calamagrostis canadensis, Carex spp., Castilleja septentrionalis, Chrysanthemum leucanthemum, Conioselinum chinese, Cornus stolonifera, Diervilla lonicera, Equisetum arvense, Equisetum variegatum, Fragaria virginiana, Gentiana amarella, Hedysarum alpinum var. americanum, Juncus alpinus, Listera auriculata, Myrica gale, Oxytropis campestris var. johannensis, Parnassia glauca, Prenanthes racemosa, Primula mistassinica, Rubus pubescens, Solidago spp., Tanacetum huronense var. johannense, Thalictrum polygamum, Tofieldia glutinosa, Trifolium repens, Trifolium pratense, Taraxacum officinale, Vicia cracca, and Viola novae-angliae. The upland forest adjacent to (and sometimes overhanging) Pedicularis stands commonly consists of the conifers Abies balsamea, Picea rubens, Picea glauca, Thuja occidentalis, with scattered broadleaf species, Acer spicatum, Betula lutea, and Populus balsamifera (USFWS 1991, Virginia Tech 2001).

  Pedicularis furbishiae is recorded only from a 225-kilometer reach of the St. John River in Northern Maine (Aroostook County) and adjacent New Brunswick.

Number Left
  Populations of Pedicularis furbishiae fluctuate in numbers and location dramatically from year to year, and are notoriously difficult to delineate (Gregory and Gawler 1990). However, the U. S. Fish and Wildlife Service (1991) estimated the total population to be 13,800 non-reproductive individuals and 4,300 flowering individuals (an increase from the approximately 5,000 stems estimated in 1980).


Global Rank:  
Guide to Global Ranks
Federal Status:  
Guide to Federal Status
Recovery Plan:  

State/Area Protection
  State/Area Rank Status Date  
  Canada N1 E 11/1/2001  
  Maine S2 E 7/1/1999  
  New Brunswick S1 E 6/6/1991  
  United States N1 12/17/1994  

Conservation, Ecology & Research

Ecological Relationships
  The origin of Pedicularis furbishiae in North America is speculative, and has some bearing on its conservation biology. The species is highly distinct in morphology from its North American congeners, and very dissimilar from the two other Pedicularis species with which it occurs in northeastern North America (Gawler 1988). It may be a relatively recent (Holocene) arrival from Asia, dispersing along deglaciation fronts. The species exhibits extremely low genetic diversity, possibly reflecting founder effects from a single small colonization event (Waller et al. 1988); this may contribute to its vulnerability.

Pedicularis furbishiae is an herbaceous perennial plant that can take up to three years to reach reproductive maturity (USFWS 1991). Tiny seedlings emerge, usually favoring wet soil, in June and July (Gawler et al. 1987). Mature plants leaf out in late May, when flood waters recede and before the majority of other plants have leafed out.

Plants reproduce solely by sexual reproduction, and can successfully self-pollinate as well as out-cross (Waller et al. 1988).

The common bumblebee, Bombus vagans, is the primary pollinator (Macior 1978).

Reproductive output is positively correlated with age (and size) of the plant (Gawler et al. 1987).

The proportion of seeds that successfully mature is regulated by pre-dispersal herbivory on the parent plant, and by a seed predator, the plume moth, Amblyptilia picta (Menges et al. 1986).

Seeds mature and disperse in the fall and are likely dispersed by wind and water, but the majority of seedlings appear to establish under or close to the parent plant.

Like many members of the Scrophulariaceae, Pedicularis furbishiae is thought to be a hemi-parasite (Musselman and Mann 1977), relying on haustorial root connections with a host plant to derive some of its nutrients. Nitrogen levels are low in the soils in its habitat (Virginia Tech 2001), so this symbiosis may be important in fostering early growth of the plant. No haustorial connections have been observed in the field (USFWS 1991), but excavation is difficult, making such connections hard to detect.

Cultivation experiments at the New England Wild Flower Society (NEWFS) have grown Pedicularis furbishiae seedlings with little bluestem grass and with clover (Trifolium sp.) to test for potential hemi-parasitism, but survivorship was poor (W. E. Brumback, NEWFS, personal communication). Host-specificity and the role of hemi-parasitism in the persistence of this species remains a mystery.

Extensive demographic modeling using data on this plant indicate that the global population persists through a dynamic series of local extinctions (brought on by ice scour) and recolonization events (Gawler 1988, Menges 1990). In fact, this species provided one of the first model systems for studying such metapopulation dynamics, contributing to new paradigms in the science of conservation biology (Schemske et al. 1994).

New demographic analyses have produced more refined projections for the future of Pedicularis furbishiae (e.g., Silvertown et al. 1996). However, the data still reinforce the notion that a whole-watershed approach is necessary to protect the large-scale dynamic processes that maintain multiple, ephemeral, mobile populations of this and other neighboring riverine species on the landscape.

  As articulated by Stirrett (1980), Day (1983), USFWS (1991), and references therein, this species is threatened by:

Garbage dumping and excavation along gravel shores that reduces habitat availability
Forestry practices (upland clearing) that increase water flows and raise the risk of catastrophic flood
Clearing and development of river shores that destroys potential habitat and increases river pollution (most of the land adjacent to the river is in private, non-conservation ownership)
Low population sizes, low genetic heterogeneity, and extremely restricted spatial distribution can contribute to high extinction probabilities due to founder effects and inbreeding depression
Damming for hydroelectric power has been proposed at various times along the river; while new projects are not underway, pressure to alter river flows remains an ongoing threat
Climate change that changes the annual cycles of icing and melting along the St. John River is a long-term, but real, threat
Snowmobiles and all-terrain vehicles threaten the upland railroad population of Pedicularis furbishiae in New Brunswick
Succession to dense shrub cover already affects an upland population in New Brunswick; increased prevalence of invasive riverine plant species could potentially pose a threat to the taxon, which is moderately shade-tolerant but grows optimally in areas of sparse vegetation

Current Research Summary
  Eric Menges (Archbold Biological Station, Lake Placid, Florida) has conducted numerous studies on the demography and biology of Pedicularis furbishiae.

Susan C. Gawler (Maine Natural Areas Program, Augusta, Maine) completed her dissertation on the ecology of the taxon.

Jonathan Silvertown (Open University, United Kingdom) uses Pedicularis furbishiae as a model system for studying the demography of rare plants (for a description of his work in collaboration with Miguel Franco (Universidad Autonoma de Mexico, Mexico City).

The New England Wild Flower Society (Framingham, Massachusetts) has conducted germination trials on Pedicularis furbishiae. Seeds treated with moist cold germinate well, and seeds stored for three years were able to germinate. However, survivorship following germination, even when experimenting with host plants, has been poor.

C. Wheeler (University of Akron, Akron, Ohio) performed experiments on seedling development and hemiparasitism in 1980 toward a Master's thesis.

Current Management Summary
  Volunteer task forces of the New England Plant Conservation Program (NEWFS), along with other conservation organizations (e.g., U. S. Fish and Wildlife Service, Maine Natural Areas Program), periodically monitor populations of Pedicularis furbishiae in New England

The Nature Trust of New Brunswick established a protected zone called the George Stirrett Nature Preserve around one of the three Canadian populations in 1990 (COSEWIC 2001). A plan existed in 1998 to transplant certain vulnerable plants from an eroding site to this preserve (Hinds 1998); but updates are needed.

The Maine Natural Areas Program has been involved with landowner education regarding Pedicularis furbishiae for over a decade (U. S. Fish and Wildlife Service 1991)

Cooperative agreements are being forged between the United States and Canada regarding joint protection of several endangered species, including Pedicularis furbishiae.

Research Management Needs
  On-going long-term tracking of the locations and demography of old and new populations is needed throughout the St. John River
Ecological studies to determine factors that limit recruitment of seeds and seedlings to available habitat
Studies of the importance of hemi-parasitism in the persistence of this species
Quantitative hydrological studies that monitor changes in flooding and ice-scouring along the river and their impacts on the plant

Ex Situ Needs
  Replicated studies of factors limiting seedling survival, including the need for a host-plant and possible techniques for propagation and reintroduction, are needed.


Books (Single Authors)

Crow, G.E. 1982. New England's rare, threatened, and endangered plants. Washington, D.C.: U.S. Government Printing Office. 169p.

Scoggan, H.J. 1978. The Flora of Canada. National Museums of CA, Publications in Botany.

Books (Sections)

Kartesz, J.T. 1999. A synonymized checklist of the vascular flora of the U.S., Canada, and Greenland. In: Kartesz, J.T.; Meacham, C.A., editors. Synthesis of the North American Flora, Version 1.0. North Carolina Botanical Garden. Chapel Hill, NC.

Pavlik, B.M. 1994. Demographic monitoring and the recovery of endangered plants. In: Bowles, M.L.; Whelan, C., editors. Recovery and Restoration of Endangered Species. Cambridge University Press. Cambridge. p 322-350.

Pavlovic, N.B. 1994. Disturbance-dependent persistence of rare plants: anthropogenic impacts and restoration implications. In: Bowles, M.L.; Whelan, C., editors. Recovery and Restoration of Endangered Species. Cambridge University Press. Cambridge. p 159-193.

Weller, S.G. 1994. The relationship of rarity to plant reproductive biology. In: Bowles, M.L.; Whelan, C., editors. Recovery and Restoration of Endangered Species. Cambridge University Press. Cambridge. p 90-117.

Electronic Sources

COSEWIC. (2001). Species at Risk. [Web site] Environment Canada; Committee on the Status of Endangered Wildlife in Canada. http://www.speciesatrisk.gc.ca/species/English/Default.cfm. Accessed: 2002.

NatureServe. (2008). NatureServe Explorer: An online encyclopedia of life [web application]. [Internet].Version 7.0. NatureServe, Arlington, Virginia. http://www.natureserve.org/explorer. Accessed: (June 17, 2008).

Journal Articles

Balis-Larsen, M.; Dauphine, C.; Jewell, S. 1999. Canada and U.S. Save Shared Species at Risk. Endangered Species Bulletin. 24, 2: 22-23.

Day, R.T. 1983. A survey and census of the endangered Furbish lousewort, Pedicularis furbishiae, in New Brunswick. Canadian Field-Naturalist. 97: 325-327.

Furbish, K. 1881. A botanist's trip to "The Aroostook.". American Naturalist. 15: 469-470.

Gawler, S.C. 1989. A Demographic Model for Pedicularis furbishiae, with Implications for Conservation Strategies. Rhodora. 91, 865: 153-153.

Gawler, S.C.; Waller, D.M.; Menges, E.S. 1987. Environmental Factors Affecting Establishment and Growth of Pedicularis furbishiae, a Rare Endemic of the St. John River Valley, Maine. Bulletin of the Torrey Botanical Club. 114, 3: 280-292.

Macior, L.W. 1978. The pollination ecology and endemic adaptation of Pedicularis furbishiae S. Wats. Bulletin of the Torrey Botanical Club. 105, 4: 268-277.

Macior, L.W. 1980. The population ecology of Furbish's Lousewort (Pedicularis furbishiae S. Wats.). Rhodora. 82: 105-111.

Macior, L.W. 1981. The Furbish Lousewort--weed, weapon, or wonder?. The American Biology Teacher. 43: 323-326.

Menges, E.S. 1986. Predicting the future of rare plant populations: demographic monitoring and modeling. Natural Areas Journal. 6: 13-25.

Menges, E.S. 1990. Population viability analysis for an endangered plant. Conservation Biology. 4: 52-62.

Menges, E.S.; Gawler, S.C. 1986. Four-year changes in population size of the endemic plant Furbish's Lousewort: implications for endangerment and management. Natural Areas Journal. 6: 6-16.

Menges, E.S.; Waller, D.M.; Gawler, S.C. 1986. Seed set and seed predation in Pedicularis furbishiae, a rare endemic of the St. John River, Maine. American Journal of Botany. 73: 1168-1177.

Musselman, L.J.; Mann, W.F., Jr. 1977. Host plants of some Rhinanthoidea (Scrophulariaceae) of eastern North America. Plant Systematics Evolution. 127: 45-53.

Schemske, D.W.; Husband, B.C.; Ruckelshaus, M.H.; Goodwillie, C.; Parker, I.M.; Bishop, J.G. 1994. Evaluating approaches to the conservation of rare and endangered plants. Ecology. 75, 3: 584-606.

Silvertown, J.; Franco, M.; Menges, E. 1996. Interpretation of elasticity matrices as an aid to the management of plant populations for conservation. Conservation Biology. 10, 2: 591-597.

USFWS. 1976. Proposed Endangered Status for 1700 U.S. Plants. Federal Register. 41: 24523-24572.

USFWS. 1978. Determination that 11 plant taxa are endangered species and 2 plant taxa are threatened species. Federal Register. 43, 81: 17910-17916.

USFWS. 1978. Furbish Lousewort Among 13 Plant Taxa Newly Listed by Service for Protection. Endangered Species Technical Bulletin. 3, 5: 1, 7-8.

USFWS. 1981. Regional Briefs--Region 5. Endangered Species Technical Bulletin. 6, 12: 6.

USFWS. 1984. Regional Briefs--Region 5. Endangered Species Technical Bulletin. 9, 4: 11.

Waller, D.M.; O'Malley, D.M.; Gawler, S.C. 1987. Genetic variation in the extreme endemic Pedicularis furbishiae (Scrophulariaceae). Conservation Biology. 1, 4: 335-340.


1999. Rare Plant Fact Sheets. Augusta, Maine, USA: Maine Department of Conservation, Natural Areas Division.

Gregory, L.L.; Gawler, S.C. 1990. Population sizes of Furbish's lousewort, Pedicularis furbishiae, 1980-1989. Augusta, Maine: Report to the Office of Endangered Species, U. S. Fish and Wildlife Service, Region 5. Critical Areas Program. p.24.

Macior, L.W. 1977. Physiological studies on Pedicularis furbishiae, Allagash, Maine. Waltham Massachusetts: U.S. Army Corps of Engineers. p.24.

Menges, E.S. 1988. Conservation biology of Furbish's Lousewort. U.S. Fish & Wildlife Service, Region 5. p.55.

Stirrett, G.M. 1980. The status of Furbish's Lousewort, Pedicularis furbishiae S. Wats., in Canada and the United States. Ottawa, Ont.: Canadian Wildlife Service. p.78.

USFWS. 1983. Furbish lousewort recovery plan. Newton Corner, Massachusetts: U.S. Fish and Wildlife Service. p.31.

USFWS. 1991. Revised Furbish lousewort (Pedicularis furbishiae) Recovery Plan. Newton Corner, Massachusetts: U. S. Fish and Wildlife Service Region Five. p.62.


Gawler, Susan Cochran. 1988. Disturbance-mediated Population Dymanics of Pedicularis furbishiae S. Wats., a Rare Riparian Endemic. [Ph.D. Thesis]: University of Wisconsin. Madison, Wisconsin. 195p.

Kite, J. S. 1983. Late quaternary glacial, lacustrine, and alluvial geology of the upper St. John River basin, northern Maine and adjacent Canada. [Ph.D. Thesis]: University of Wisconsin. Madison, Wisconsin. 339p.

Wheeler, C.E. 1980. Seedling development and root parasitism in Pedicularis furbishiae S. Wats. [M.S. Thesis]: University of Akron. Akron, Ohio. 61p.

  This profile was updated on 3/4/2010
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