The following Participating Institutions are custodians for this species in the CPC National Collection:
The North Carolina Arboretum
The conservation of Crataegus harbisonii is fully sponsored.
Ron Lance contributed to this Plant Profile.
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
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)
|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).|
Conservation, Ecology & Research
Like most hawthorns, C. harbisonii is susceptible to a number of
Cultivation efforts (from grafts) at the North Carolina Arboretum found that this species can not tolerate
Lance, R.W. 1994. The hawthorns of the southeastern United States. Published by the author.
Sargent, C.S. 1905. Manual of the trees of North America. Boston and New York: Houghton, Mifflin Co.
Sargent, C.S. 1922. Manual of the trees of North America. Boston and New York: Houghton, Mifflin Co.
Sargent, C.S. 1947. The silva of North America. Supplement, Vol 13. NY: Peter Smith.