''Prunus geniculata'' is a rare species of plum known by the common name scrub plum. The species is

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found else ...

Florida Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, and to ...

Description

This plant is a low, rounded shrub with a gnarled trunk emerging from the sand and branching densely to form a mound up to two meters tall. The zig-zagging, angled, sharp-tipped branches are sometimes buried in sand and emerge covered in lichens. The gray bark cracks, revealing new reddish brown bark beneath. The alternately arranged leaves have smooth blades 1 to 3 centimeters long with wavy or toothed edges. Blooming occurs before the leaves appear. The flowers are usually solitary. They have five red

sepal A sepal () is a part of the flower of angiosperms (flowering plants). Usually green, sepals typically function as protection for the flower in bud, and often as support for the petals when in bloom., p. 106 The term ''sepalum'' was coine ...

s and five white petals a few millimeters long. There are many stamens at the center, each with a yellow anther. The species is

andromonoecious Andromonoecy is a breeding system of plant species in which male and hermaphrodite flowers are on the same plant. It is a monomorphic sexual system alongside monoecy, gynomonoecy and trimonoecy. Andromonoecy is frequent among genera with zygomor ...

, with individuals bearing both bisexual and male-only flowers.''Prunus geniculata''.
Center for Plant Conservation.Weekley, C. W., et al. (2010)
Multiple causes of seedling rarity in scrub plum, ''Prunus geniculata'' (Rosaceae), an endangered shrub of the Florida scrub.
''Am J Bot'' 97(1) 144. The fruit is a bitter-tasting, egg-shaped drupe up to 2.5 centimeters long.''Prunus geniculata''.
The Nature Conservancy. The drupe is reddish purple in color. The plant may be solitary or it may grow colonially. Little is known about the plant's life history.

Distribution and habitat

The species is

in the United States, where it occurs on the

Lake Wales Ridge The Lake Wales Ridge, sometimes referred to as the Mid-Florida Ridge,Eastern States Archaeological Federation. ''Archaeology of Eastern North America, Volume 11'', p. 54 is a sand ridge running for about 150 miles south to north in Central Florida. ...

in the central ridges of the peninsula. It grows in yellow-sand

sandhill A sandhill is a type of ecological community or xeric wildfire-maintained ecosystem. It is not the same as a sand dune. It features very short fire return intervals, one to five years. Without fire, sandhills undergo ecological succession and bec ...

habitat dominated by

longleaf pine The longleaf pine (''Pinus palustris'') is a pine species native to the Southeastern United States, found along the coastal plain from East Texas to southern Virginia, extending into northern and central Florida. In this area it is also known as ...

and

turkey oak Turkey oak is a common name for several species of oaks and may refer to: *''Quercus cerris'', native to southeastern Europe and Asia Minor *''Quercus laevis ''Quercus laevis'', the turkey oak, is a member of the red oak group of oaks. It is n ...

and white-sand

Florida scrub Florida sand pine scrub is an endangered subtropical forest ecoregion found throughout Florida in the United States. It is found on coastal and inland sand ridges and is characterized by an evergreen xeromorphic plant community dominated by shrub ...

among

sand pine ''Pinus clausa'' is a species of pine endemic to the Southeastern United States. Its common names include sand pine, Florida spruce pine, Alabama pine, and scrub pine. Distribution The tree is found in two separate locations, one across central ...

, Florida rosemary, and

scrub hickory ''Carya floridana'' (syn. ''Hicoria floridana'') the scrub hickory, is a tree native to the Southeast United States, where it is endemic in central Florida. Although it can grow to the height of 25 m (80 ft), many specimens are seen as shrubs 3� ...

. As of 2008 there were 83 populations counted, but 39 of these contained fewer than 10 plants each. Most populations are on the Lake Wales Ridge, and a few are on adjacent ridges. Half the populations are on private land, but most of the large populations are in protected or managed areas.

Ecology

The plant's native habitat is maintained by periodic

wildfire A wildfire, forest fire, bushfire, wildland fire or rural fire is an unplanned, uncontrolled and unpredictable fire in an area of combustible vegetation. Depending on the type of vegetation present, a wildfire may be more specifically identi ...

. The natural

fire regime A fire regime is the pattern, frequency, and intensity of the bushfires and wildfires that prevail in an area over long periods of time. It is an integral part of fire ecology, and renewal for certain types of ecosystems. A fire regime describes th ...

in the area produces openings in the vegetation, removing woody, overgrown plants in the

canopy Canopy may refer to: Plants * Canopy (biology), aboveground portion of plant community or crop (including forests) * Canopy (grape), aboveground portion of grapes Religion and ceremonies * Baldachin or canopy of state, typically placed over an ...

and creating gaps where the smaller plants can receive sun. This shrub cannot tolerate shade and it thrives when fire clears the vegetation around it. It resprouts from its fibrous root system after its aboveground part burns. Flowering increases in the seasons after a fire, then decreases the longer the area goes unburned. The plant is long-lived, has low mortality, and can survive many years without fire. However,

fire suppression Wildfire suppression is a range of firefighting tactics used to suppress wildfires. Firefighting efforts in wild land areas require different techniques, equipment, and training from the more familiar structure fire fighting found in populated ...

is the major threat to the survival of the species.USFWS
''Prunus geniculata'' Five-year Review.
May 2009. Due to the loss of its habitat, the plant is federally listed as an endangered species of the U.S. Another threat to the species is the outright loss of its habitat in the conversion to residential and agricultural properties, including

citrus ''Citrus'' is a genus of flowering trees and shrubs in the rue family, Rutaceae. Plants in the genus produce citrus fruits, including important crops such as oranges, lemons, grapefruits, pomelos, and limes. The genus ''Citrus'' is native to ...

groves. The plant's own biology may contribute to its rarity: germination rates are low and many of the developing fruits are lost before they mature, either to abortion or predation. The species then experiences low recruitment, with few seedlings joining the population. The drupe is consumed by animals.

References

External links

USDA Plants Profile
{{Taxonbar, from=Q7253106 geniculata geniculata Plants described in 1911 Endemic flora of Florida