Scrub Plum

Prunus geniculata

Description

Scrub plum, Prunus geniculata, is a scraggly, heavily branched shrub up to 6 ft (2 m) tall, with spiny branches and stems. Its finely toothed deciduous leaves are rounded. Numerous fragrant, small, white, five-petaled flowers bloom in winter. The fruit is a bitter, dull red plum. The bark of new shoots is lustrous reddish-brown or purplish, becoming lustrous gray and longitudinally cracked as the branch ages. The bark of old stems is thin and gray, usually lichen-encrusted, forming small rectangular or square plates.

Habitat

Scrub plum occurs in pine scrub or pine rockland habitat and is sometimes a component of the longleaf pine-turkey oak community. It is found along road cuts and fire lanes, which indicates that it benefits from moderate disturbance that removes other shrubs. Scrub plum is adapted to fire. Dozens of rare plants are endemic to sand pine scrub in south-central Florida, including the federally endangered pygmy fringe tree (Chionanthus pygmaeus ).

Distribution

Scrub plum was first collected in 1911 from Lake County, Florida, and is thought to be endemic to central and southern Florida. In Lake County, the scrub plum occurred in longleaf pine-turkey oak forests near Lake Apopka and Lake Eustis. These forests have been destroyed except for a few small remnants, and it is difficult to reconstruct the role of the plum and the pygmy fringe tree in this area. These habitat areas have been destroyed due to development projects and conversion of the lands to citrus orchards.

Today, scrub plum is found in two general areas in central Florida: in Lake County between Lake Apopka and Clermont, and in Polk and Highlands Counties from Lake Wales south along the Lake Wales Ridge. Since not all scrub vegetation contains scrub plum, remaining stands of the shrub are very limited. Still, nearly 50 populations, each containing at least several shrubs, have been identified.

Scrub plum has been located at the Pine Ridge Nature Reserve of Bok Tower Gardens near Lake Wales, at Saddle Blanket Lakes in Polk County, and at the Nature Conservancy's Tiger Creek Preserve in Polk County.

Threats

Much of the pine scrub habitat within the plant's range in Lake County has been developed for citrus groves or for residential subdivisions. Disjunct remnants of habitat survive as vacant lots or along railroad rights-of-way. Tracts of scrub in Highlands and Polk Counties are rapidly succumbing to developmental pressures. Scrub vegetation is maintained by periodic fires, which create areas of bare, sunny sand that the scrub plum and other plants can colonize; but fire has been suppressed throughout the plant's range. The pattern of long-interval, high-intensity fire is essential to maintaining the sand pine scrub vegetation; without fire, the vegetation will gradually change to xeric hardwood forest

Conservation and Recovery

Current efforts by the Florida Natural Areas Inventory to acquire parcels of sand pine scrub in Highlands and Polk Counties may remove some of the developmental pressures on threatened scrub species. Two preserves purchased by the Nature Conservancy (Saddle Blanket Lakes and Tiger Creek) have already benefited the scrub. More land may be purchased by the State of Florida, Department of Natural Resources. Preserve management will require occasional burning (on a schedule that may include up to 80 years between fires).

A U. S. Fish and Wildlife Service (FWS) draft recovery plan for 19 Florida scrub and high pineland plants, first announced in 1995, outlines basic elements necessary to restore the scrub plum and other endangered plants, including habitat protection through land purchase and other means (including the habitat conservation plan process for threatened animals in the Florida scrub habitat); the management of protected habitats; and the assessment of progress and plan post-recovery monitoring.

This plan is a revision and expansion of a recovery plan, published in 1990, that covered 11 of these plant species. The 1990 edition emphasized the need for land acquisition to protect these plants. At the time, the state and private organizations had already made significant acquisitions, and more have been accomplished since then (including initial land purchase for the Lake Wales Ridge National Wild-life Refuge). These land purchases, accompanied by the other elements of the recovery plan, are likely to assure the full recovery or at least the downlisting of the large majority of the 19 plants, including the scrub plum.

Contact

U. S. Fish and Wildlife Service
Regional Office, Division of Endangered Species
1875 Century Blvd., Suite 200
Atlanta, Georgia 30345
http://southeast.fws.gov/

References

Abrahamson, W. G. 1984. "Post-Fire Recovery of the Florida Lake Wales Ridge Vegetation." American Journal of Botany 71:9-21.

Abrahamson, W. G., et al. 1984. "Vegetation of the Archbold Biological Station, Florida." Florida Scientist 47:209-250.

U. S. Fish and Wildlife Service. 1995. "(draft) Recovery Plan for Nineteen Florida Scrub and High Pineland Plants." U. S. Fish and Wildlife Service, Atlanta.

Ward, D. B., ed. 1979. Rare and Endangered Biota of Florida ; Vol. 5, Plants. University Presses of Florida, Gainesville.

Wunderlin, R. P. 1982. Guide to the Vascular Flora of Central Florida. University Presses of Florida, Gainesville.