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Photo of Scrub Lupine courtesy of Shirley Denton
FAMILY: Fabaceae (Pea family)
STATUS: Endangered (Federal Register, April 7, 1987)
DESCRIPTION: Scrub lupine is a biennial or short-lived perennial growing from a soft woody base; the stems are up to 1 meter (3 feet) tall. Its leaves are obovate-elliptic in shape, 4 to 7 centimeters (1.5 to 2.8 inches) long, and 2 to 4 centimeters (0.8 to 1.5 inches) wide. The ends of the leaves are rounded, with sharp pointed tips and the bases are rounded; the upper and lower surfaces are covered with silvery hairs. The petioles are 2 to 4.5 centimeters (0.8 to 1.8 inches) long; the stipules are very small. The inflorescences are racemose with stalks 4 to 13 centimeters (1.5 to 5.2 inches) long, and the flowering portion 4 to 15 centimeters (1.5 to 5.8 inches) long. The petals are pale flesh-pink except for the standard, which has a black center surrounded by a maroon red area. The standard is about 1.5 centimeters (0.5-inch) long, and the keel petals slightly shorter. The fruit is 2 to 2.5 centimeters (0.8 to 1-inch) long, woody, and elliptic in shape, tapering to a sharp apex.
This plant is distinctive in the field, being the only upright pink-flowered lupine in Florida. It is further distinguished from the only other pink-flowered lupine, the prostrate Lupinus villosus, by the lack of long, shaggy hairs on stems and leaves, and vestigial (rather than large and conspicuous) stipules. It is most closely related to Lupinus westianus of the Florida Panhandle, but differs in flower color. Lupinus westianus has blue flowers.
RANGE AND POPULATION LEVEL: Endemic to Central Florida, scrub lupine occurs only in Polk County (12 sites), Orange County (32 sites), and Osceola County (1 site) (TNC 1999). In 1998, the total population consisted of about 1000 plants and 500 seedlings; the site with the largest population has about 450 plants and 60 seedlings. In Orange County, the plant's known range is between the City of Orlando and Walt Disney World. In Polk County, it is found between Winter Haven and Auburndale. In Osceola County, scrub lupine is known to occur on only one site at Celebration (TNC 1999).
HABITAT: This plant is a sand pine (Pinus clausa) scrub species that grows primarily in well-drained sandy soils of the Lakewood or St. Lucie series, or what is generally to have been sand pine and rosemary (Ceratiola ericoides). The sands are white or occasionally yellow where the turkey oak woods have invaded the sand pine scrub. The tree layer may be a mixture of sand pine, Pinus elliotii (slash pine), and Quercus laevis (turkey oak) (Wunderlin 1982). The scrub layer is usually sparse, possibly as a result of disturbance at many of the sites where the lupine occurs.
REASONS FOR CURRENT STATUS: Most of the plants occur in habitats that have already been highly modified, or that are threatened by housing developments, road construction and maintenance, conversion to pastureland, exotic encroachment, and by pedestrian, horse, and off-road vehicular traffic. The plant's attractiveness also exposes it to the possibility of being taken for horticultural purposes. A final factor is that the species rareness makes it all the more vulnerable to disturbance and natural disasters.
MANAGEMENT AND PROTECTION: Thirty-four of the 45 known habitat sites for Lupinus aridorum are located on private property in areas that are undergoing rapid development (The Nature Conservancy 1999). Preservation of the species will require finding a means to preserve a sufficient number of these sites to ensure the species long-term survival. Establishing new populations on protected lands will likely be required for recovery (T. Race, Bok Tower Gardens, pers. comm.). Fire management is not an issue for this species at this time; mechanical control of woody vegetation is more likely the management methodology which will be needed (J. Stout, University of Central Florida, pers. comm.). A recent non-scientific study performed by Sverdrup (in. litt. 1999) noted 2 lupine seedlings were discovered in an area not previously occupied; the area had been raked in an effort to stimulate the seed bank. Additional work is needed to determine the feasibility of this technique as a recovery tool.
The Nature Conservancy. 1999. Conservation Plan for Lupinus aridorum. Report of February 1998 meeting. The Nature Conservancy, Lake Wales Ridge Program, September 25, 1999. 9 pages.
U.S. Fish and Wildlife Service. 1987. Endangered and Threatened Wildlife and Plants; Proposed Endangered Status for Lupinus aridorum (scrub lupine). Federal Register 52(66): 11172-11175.
Wunderlin, R. P. 1982. Guide to the Vascular Plants of Central Florida. University Press of Florida, Gainesville. 472 pages.
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Last Updated: 08/2009
PDF Version - 187KB