The following Participating Institutions are custodians for this species in the CPC National Collection:
The Holden Arboretum
Missouri Botanical Garden
The conservation of Dalea foliosa is fully sponsored.
Kimberlie McCue, Ph.D. contributed to this Plant Profile.
Dalea foliosa is a perennial in the legume family (Fabaceae) that produces dense clusters of small purple flowers in early August. Leafy prairie-clover was first observed and documented in the late 1850's. Since then, known occurrences of the species have declined dramatically due to habitat destruction, overgrazing, and habitat loss due to fire suppression (USFWS 1996). One historic population of Dalea foliosa in Illinois was eliminated through overcollection, and at least one population in Alabama was likely extirpated by road maintenance and storm sewer installation.
Distribution & Occurrence
Dalea foliosa is found only in the open habitat of limestone cedar glades, limestone barrens, and thin-soiled mesic dolomite prairies (Baskin and Baskin 1973). All of these habitats share a few features, such as high soil temperature, high soil moisture in the spring and fall, and low soil moisture in the summer (Baskin and Baskin 1973).
|Two to four populations in Alabama and Illinois, the majority of sites occur in Central Tennessee (~20). Most populations have fewer than 100 plants (USFWS 1996).|
Conservation, Ecology & Research
Very few Dalea foliosa seedlings survive to maturity, as they are killed by summer drought and frost heave. In a demographic study at a site in Illinois, only about 5% of all seedlings survived to the age of 5 years. The oldest plants monitored to date lived to be 8 years old (Bowles and Jones 1992).
Habitat degradation by woody plant succession and exotic species invasion
Extended summer drought
In Illinois, frost heave, severe rabbit grazing and drought were found to
A preliminary genetic study assessed diversity of the species throughout its range (Wiltshire 1994). Genetic diversity is relatively low, with nearly all variation occurring among Tennessee populations.
Seeds collected in Illinois were germinated, and juvenile plants were transplanted to re-created habitat that features endangered and threatened plants at the Morton Arboretum in Lisle, Illinois. This site functions as source material for restoration and recovery projects as well as an educational exhibit.
Population viability indexes have been assigned to all extant populations. Targets have been set for recovery efforts, and the criteria that need to be met for delisting to occur have been delineated.
From a management perspective, historic locations of this species need to be searched out and their restoration potential assessed. If restoration is possible, management methods, perhaps including a prescribed burning regime, should be implemented to trigger the germination of any seeds in the seed bank. If this is unsuccessful, reintroduction of the species should be considered. In addition, it is important to maintain the habitat quality of this species, which involves management that keeps woody plants and invasive species encroachment at bay.
Baskin, J.M.; Baskin, C.C. 1973. The Past and Present Geographical Distribution of Petalostemon foliosus and notes on its ecology. Rhodora. 75: 132-140.
Baskin, J.M.; Baskin, C.C. 1986. Distribution of geographical-evolutionary relationships of cedar glade endemics in southeastern USA. ASB Bulletin. 33, 4: 138-154.
Schwegman, J.E. 1991. The vascular flora of Langham Island, Kankakee County, Illinois. Erigenia. 11: 1-8.
USFWS. 1991. Dalea foliosa (leafy prairie-clover) determined to be endangered. Federal Register. 56, 84: 19953 - 19959.
USFWS. 1998. 90-Day Finding for a Petition To List Agave eggersiana and Solanum conocarpum as Endangered. Federal Register. 63, 220: 63659-63661.