CPC Plant Profile: Leafy Prairie-clover
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Plant Profile

Leafy Prairie-clover (Dalea foliosa)

Seed heads (resembling tiny corncobs) on skinny, tall stalks. Photo Credit: Kimberlie McCue
Description
  • Global Rank: G2 - Imperiled
  • Legal Status: Federally Endangered
  • Family: Fabaceae
  • State: AL, IL, TN
  • Nature Serve ID: 158233
  • Date Inducted in National Collection: 02/10/1987

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.

Participating Institutions
Updates
Center for Plant Conservation
  • 08/18/2021
  • Orthodox Seed Banking

In 2021, CPC contracted the Missouri Botanical Garden to recollect seed from a population currently held in long term orthodox seed storage as part of an IMLS-funded seed longevity experiment. The National Laboratory for Genetic Resources Preservation will evaluate how germination tested viability and RNA Integrity of seed lots decline over time in storage.

  • 09/08/2020
  • Orthodox Seed Banking

Maintain ex situ seed collections for use in research and as restoration material.

  • 09/08/2020
  • Reproductive Research

Baskin and Baskin (1998) performed the only in-depth study of this species to date. They assessed the ecological life cycle of Dalea foliosa through a series of greenhouse and laboratory studies. The goals of this project included determination of dormancy-breaking and germination requirements, analysis of potential seed persistence in the seed bank, and flowering requirements and phenology. 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.

  • 09/08/2020
  • Propagation Research

Baskin and Baskin (1998) performed the only in-depth study of this species to date. They assessed the ecological life cycle of Dalea foliosa through a series of greenhouse and laboratory studies. The goals of this project included determination of dormancy-breaking and germination requirements, analysis of potential seed persistence in the seed bank, and flowering requirements and phenology.

  • 09/08/2020
  • Demographic Research

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.

  • 09/08/2020
  • Genetic Research

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.

  • 09/04/2020
  • Living Collection

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.

  • 09/04/2020
  • Seed Collection

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.

  • 09/04/2020
  • Propagation Research

A monitoring study performed by the Illinois Department of Natural Resources over the course of 7 years found that moisture was a limiting factor in mature plant vigor and seed germination (Bowles and Jones 1992). This species is fire-dependent, as the heat of a spring burn scarifies its seeds, which will then germinate if adequate moisture is available. However, it was observed that fall burning increased the likelihood and severity of winter frost heave damage.

Nature Serve Biotics
  • 05/02/2017

Since this species was first described, known occurrences have declined due to habitat destruction and alteration due to commercial and industrial development, overgrazing, and lack of fire. There are approximately 60 extant occurrences presently recorded, but about 40 occurrences are of poor or very poor quality. There are currently known extant occurrences in 3 states: 49 in Tennessee, 3 in Alabama, and 10 in Illinois. In Tennessee, 8 occurrences are ranked as good or excellent. Even when protected on public or private conservation lands, populations will remain threatened by lack of fire and the resulting succession of woody vegetation if management to keep sites open is not implemented. Due to continuing land use change, the species as a whole is highly threatened by continued loss of habitat (land use change is particularly rapid in the Central Basin of Tennessee, especially so in Davidson, Rutherford, and Wilson counties). While more populations may be discovered, most will probably be marginal ones. In Tennessee, many sites are gravely threatened by exotic shrubs, particularly Chinese privet (Ligustrum sinense), sericea lespedeza (Lespedeza cuneata), and Eurasian bush-honeysuckle (Lonicera maackii).

Kimberlie McCue, Ph.D.
  • 01/01/2010

Over-collecting, trampling Habitat degradation by woody plant succession and exotic species invasion Habitat destruction Herbivore damage Extended summer drought (USFWS 1996) In Illinois, frost heave, severe rabbit grazing and drought were found to

Kimberlie McCue, Ph.D.
  • 01/01/2010

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).

Kimberlie McCue, Ph.D.
  • 01/01/2010

Baskin and Baskin (1998) performed the only in-depth study of this species to date. They assessed the ecological life cycle of Dalea foliosa through a series of greenhouse and laboratory studies. The goals of this project included determination of dormancy-breaking and germination requirements, analysis of potential seed persistence in the seed bank, and flowering requirements and phenology. 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.

Kimberlie McCue, Ph.D.
  • 01/01/2010

A monitoring study performed by the Illinois Department of Natural Resources over the course of 7 years found that moisture was a limiting factor in mature plant vigor and seed germination (Bowles and Jones 1992). This species is fire-dependent, as the heat of a spring burn scarifies its seeds, which will then germinate if adequate moisture is available. However, it was observed that fall burning increased the likelihood and severity of winter frost heave damage. 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.

Kimberlie McCue, Ph.D.
  • 01/01/2010

Research needs include an in-depth demographic study, including the cycle of dormant life stages, as well as the effect of fire on seed viability and germination . It is also important to expand on knowledge of the breeding system of the species. 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.

Kimberlie McCue, Ph.D.
  • 01/01/2010

Maintain ex situ seed collections for use in research and as restoration material.

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Photos
Nomenclature
Taxon Dalea foliosa
Authority (Gray) Barneby
Family Fabaceae
CPC Number 1350
ITIS 26615
USDA DAFO2
Common Names leafy prairie-clover | leafy prairie clover
Associated Scientific Names Dalea foliosa | Petalostemum foliosum | Petalostemon foliosus | Kuhnistera foliosa
Distribution Limestone cedar glades of central Tennessee and northern Alabama, and dolomite prairie of northeastern Illinois (Pyne et al. 1995).
State Rank
State State Rank
Alabama S1
Illinois S1
Tennessee S2S3
Habitat

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).

Ecological Relationships

Although the breeding system of Dalea foliosa is still unknown, it is likely that insect pollination by Bombus spp. (bumblebee species) is required for successful seed set, as is the case for other species in the Dalea genus. 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).

Pollinators
Common Name Name in Text Association Type Source InteractionID
Bees
Bumble bees Bombus Not Specified Link
Bees Confirmed Pollinator Link

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