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Conserving and restoring
America's native plants |
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CPC National Collection Plant Profile
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Crataegus harbisonii
| Family: |
Rosaceae (Rose Family) |
| Common Name: |
Harbison hawthorn |
| Taxon Synonym: |
Crataegus ashei |
| Author: |
Beadle |
| Growth
Habit: |
Tree |
| CPC
Number: |
1099 |
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| Primary
custodian for this plant in the CPC National Collection of Endangered
Plants is: |
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| Ron Lance contributed to this Plant Profile. |
Crataegus harbisonii
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The Harbison hawthorn is one of the rarest woody plants in the United States. After many years of research into its history, distribution, and taxonomy, several points have been made clear. The entity is distinct from other hawthorns, being closely related only to two other species in the genus. The entity has become progressively rarer in its endemic range, seemingly due to habitat changes brought on by the proliferation of exotic plant competition and fire control. The entity is currently known to be represented only a few individuals in its natural range, and by several hundred cultivated individuals.
As Lance (2000) notes, this species has had an interesting history. Early accounts of Crataegus harbisonii implied that it was endemic to Tennessee, and the Nashville area specifically, as all early collections were made from that area. An accurate image of the natural status of C. harbisonii at its time of description is difficult to substantiate, but was alluded to as "common" by Sargent (1905, 1922, 1947). Beadle (1899) reports "numerous examples" of C. harbisonii "observed at intervals during the past summer". By 1950, no further reference to abundance in the Nashville area, or in Tennessee, is noted in the literature until 1978, when the species was included in the list of "Rare Vascular Plants of Tennessee", and in 1982, when Paul Somers referred to it as "endangered" and "possibly extirpated" from its type locality in his element ranking form for the Tennessee Natural Heritage Inventory. Between 1993 and 1998, only two living specimens were discovered after extensive field searches. As of 2001, only 1 living specimen of C. harbisonii is known to remain in the type locality. However, recent searches have discovered a handful of this species in the near vicinity.
| Distribution
& Occurrence |
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State Range
Habitat
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Found in the area surrounding Nashville, Tennessee, on dry limestone outcroppings and soil overlying limestone in natural hardwood forests. (Sargent 1905; Lance 2000)
This species is found in the understory. Canopy associates include Ulmus, Fraxinus, Celtis, and Juniperus, with increased incidence of Quercus and Acer saccharum in more mesic conditions. Understory trees and shrubs such as Viburnum rufidulum, Cornus florida, Cercis canadensis, Frangula caroliniana, or Forestiera ligustrina may be common in the natural sense, but exotic Lonicera frequently dominates many sites today. (Lance 2000a) |
Distribution
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Found only in one population in Tennessee outside of Nashville. |
Number Left
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A number of plants were recently found in the wild near the type location, but all were in an area with a heavy canopy that blocks sunlight and appears to be keeping the individuals from flowering and producing seed. A number (over 100) of individuals are in cultivation at North Carolina Arboretum (Lance 2000a). |
State/Area
Protection
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State/Area |
Rank |
Status |
Date |
|
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Georgia |
SU |
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8/22/1988 |
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Tennessee |
S1 |
E |
3/1/2001 |
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| Conservation,
Ecology & Research |
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Ecological
Relationships
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Fire may play a role in the survival of this species...Although individual Crataegus tend to have bark that is poorly resistant to fire, regrowth from root systems and development from seed is rapid, and continued colonization of burned lands is a reasonable expectation for the plants. (Lance 2000a) |
Threats
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• The invasive shrub (Lonicera maackii) has altered the understory of the forests where this species was once found, likely inhibiting recruitment of this and other species. (Lance 2000a)
• Like most hawthorns, C. harbisonii is susceptible to a number of fungal and bacterial diseases as well as insect attacks. Most serious of these are the various blights and rusts which not only infect leaves, twigs, or stems of the plants, causing the death of these parts, but also destroy fruits. (Lance 2000a) |
Current Research Summary
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• Ron Lance compared this taxon with other closely related, similar, or even synonymous taxa or specimen using isozymes and found that C. harbisonii contains a unique allele, supporting the need for this taxon to be recognized as a species rather than just a morphological variant of a more common Crataegus species (C. triflora). He also found C. harbisonii to differ from the also rare C. ashei, which is often considered synonymous with C. harbisonii, while C. ashei did not differ from the common C. triflora. (Lance 2000a, 2000b)
• Cultivation efforts (from grafts) at the North Carolina Arboretum found that this species can not tolerate |
Current Management Summary
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For now, the individuals in the wild are protected within a registered State Natural Area of Tennessee and a municipal property of Nashville. The Natural Resources Staff of the park are aware of the location and significance of the plant, as are the Tennessee Natural Heritage Inventory botanists. (Lance 2000a) |
Research Management Needs
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• Removal of adjacent competing exotic plants, and thinning the overhead canopy to allow for admittance of sunlight to C. harbisonii specimens. (Lance 2000a) |
Ex Situ Needs
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| Books (Single Authors)
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| Chester, E.W.; Wofford, B.E.; Kral, R.; DeSelm, H.R.; Evans, A.M. 1993. Atlas of Tennessee vascular plants. Clarksville, Tennessee: Austin Peay State University. |
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| Lance, R.W. 1994. The hawthorns of the southeastern United States. Published by the author. |
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| Sargent, C.S. 1905. Manual of the trees of North America. Boston and New York: Houghton, Mifflin Co. |
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| Sargent, C.S. 1922. Manual of the trees of North America. Boston and New York: Houghton, Mifflin Co. |
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| Sargent, C.S. 1947. The silva of North America. Supplement, Vol 13. NY: Peter Smith. |
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| Journal Articles
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| Beadle, C.D. 1899. Studies in Crataegus I. Botanical Gazette. 28: 405-417. |
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| Beadle, C.D. 1900. Studies in Crataegus II. Botanical Gazette. 30: 325-342. |
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| Eggleston, W.W. 1910. Sketch of the Crataegus problem, with special reference to work in the south. Journal of the New York Botanical Garden. 11: 78-83. |
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| Lance, R.W.; Phipps, J.B. 2000. Crataegus harbisonii Beadle Rediscovered and Amplified. Castanea : the journal of the Southern Appalachian Botanical Club. 65, 4: 291-296. |
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| Muniyamma, M.; Phipps, J.B. 1979. Cytological proof of apomyxis in Crataegus. American Journal of Botany. 66: 149-155. |
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| Muniyamma, M.; Phipps, J.B. 1985. Studies in Crataegus XI; further cytological evidence for apomyxis in North American hawthorns. Canadian Journal of Botany. 62: 2316-2324. |
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| Palmer, E.J. 1925. Synopsis of North American Crataegi. Journal Arnold Arboretum. 6: 5-128. |
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| Palmer, E.J. 1932. The crataegus problem. Journal Arnold Arboretum. 13: 342-362. |
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| Palmer, E.J. 1944. The species concept in Crataegus. Chronicals of Botany. 7: 353-375. |
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| Phipps, J.B. 1983. Biogeographic, taxonomic, and cladistic relationships between east Asiatic and North American Crataegus. Annals of the Missouri Botanical Garden. 70: 667-700. |
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| Phipps, J.B. 1988. Crataegus (Maloideae, Rosaceae) of the southeastern United States, I. Introduction and series Aestivales. Journal Arnold Arboretum. 69: 401-431. |
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| USFWS. 1976. Proposed Endangered Status for 1700 U.S. Plants. Federal Register. 41: 24523-24572. |
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| USFWS. 1991. Conradina verticillata (Cumberland Rosemary) Determined To Be Threatened. Federal Register. 56: 60937-. |
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| USFWS. 1991. Conradina verticillata (Cumberland Rosemary) Proposed as Threatened. Federal Register. 56: 1967-1971. |
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| Reports
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| Lance, R.W. 2000. Status Report on Crataegus harbisonii and Crataegus ashei. Jackson, MS: U.S. Fish and Wildlife Service. |
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| Somers, Paul. 1982. Crataegus harbisonii, element ranking form. Code LC 189. Nashville, TN: Tenn. Natural Heritage Inventory. |
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