No Common Name
|Listed||March 7, 1995|
|Family||Gesneriaceae (African violet)|
|Description||Small, gregarious shrub; bark is smooth, gray brown, and glabrous; bears flowers and fruit.|
|Habitat||Rocky streambeds on wet serpentine rock, where water is constantly seeping.|
|Threats||Trail construction, water removal or impoundment.|
Gesneria pauciflora is a small gregarious shrub which may reach 11.8 in (30 cm) in height and 0.3 in (8 mm) in diameter. Stems may be erect or decumbent and the bark is smooth, gray brown, and glabrous. The leaves are alternate and the terete or flattened petioles are from 0.1-0.3 in (2-7 mm) long. Leaf blades are shaped like a narrow trowel, 1.1-3.6 in (2.8-9.2 cm) long and 0.4-0.9 in (0.9-2.3 cm) wide, membranous, dark green and glossy above, and pilose along the prominent veins. The margin is subentire toward the cuneate base and serrate to sublobate above. The inflorescences are one to few-flowered and the peduncles from 2.4-6.0 in (6.1-15.3 cm) long and slightly curved. The pedicels are 0.4-0.8 in (1-2 cm) long, reddish brown, and pilose to glabrescent. The corolla is tubular, curved, 0.8-0.9 in (2-2.3 cm) long, 0.12 in (4 mm) wide at the base, narrowing to 0.1 in (3 mm) but widening to 0.2 in (5 mm) at the middle and again narrowing to 0.12 in (4 mm) at the mouth. The five-lobed corolla is yellow to yellow-orange and densely pilose outside but glabrous inside. The fruit is a capsule, approximately 0.12 in (4 mm) long and wide, gray-brown, glabrescent, with five to 10 not prominent ridges.
At all known localities the species are found growing in rocky streambeds on wet serpentine rock, where water is constantly seeping. The plants may be submerged for a short time during periods of high water. The Maricao and Seco River localities are found within the Maricao Commonwealth Forest, managed by the Puerto Rico Department of Natural and Environmental Resources. However, the Lajas River population lies at the edge of the forested area; it is not certain whether the site falls within commonwealth forest property. The largest population is located in an area of steep unstable slopes and may be threatened by landslides and flood damage. Forest management practices such as trail construction may adversely affect the species.
G. pauciflora is a small shrub currently known from only three populations in the western mountains of Puerto Rico. The German botanical collector Paul Sintenis discovered it on December 3, 1884, at "Indiera Fria" in Maricao, Puerto Rico. Numerous other botanists collected the plant from this same location throughout the years. A second population was discovered later in the municipality of Sabana Grande near the headwaters of the Seco River, and a third was found from a small tributary of the Lajas River. Herbarium specimens indicate that the species has also been collected in the past from the Yaguez River and from Cerro Las Mesas. Population estimates are difficult due to the plant's habit of growing in dense mats; however, the largest population, Maricao River, has been estimated at approximately 1,000 individuals and the second, Seco River, at 50 individuals. Plants are known to occur in clusters of few to numerous individuals. Each population consists of clusters or colonies of individuals. The population of the Maricao River consists of 12 colonies, the Seco River of three, and the Lajas River of two.
Although at least two of the populations of G. pauciflora are found within the Maricao Commonwealth Forest, a management plan for the forest has not been prepared. Activities within the forest may increase the potential for erosion of the steep unstable slopes where the species occurs. Management practices such as trail construction may directly affect the species. Because the plant has not been found more than 3.3 ft (1 m) above or away from the water, any water removal upstream or water impoundment downstream may adversely affect this plant. Due to water shortages experienced by the whole island, the number of proposed water intakes has increased, which would result in a lower flow of water.
One of the most important factors affecting the continued survival of this species is its limited distribution. Because so few individuals are known to occur in a limited area, the magnitude of threat is extremely high. Landslides, floods and storm damage are natural occurrences that may affect the steep, unstable slopes associated with the species' habitat.
Conservation and Recovery
The Commonwealth of Puerto Rico has adopted a regulation that recognizes and provides protection for certain commonwealth listed species. However, G. pauciflora is not yet on the commonwealth list. Federal listing provides immediate protection, and pending placement of the species on the commonwealth list will ultimately enhance its protection and increase the potential for funding of needed research.
U.S. Fish and Wildlife Service
Regional Office, Division of Endangered Species
1875 Century Blvd., Suite 200
Atlanta, Georgia 30345
Caribbean Field Office
U.S. Fish and Wildlife Service
P.O. Box 491
Boquerón, Puerto Rico 00622
Center for Plant Conservation. 1992. "Report on the rare plants of Puerto Rico." Center for Plant Conservation, Missouri Botanical Garden, St. Louis.
Proctor, G. R. 1991. "Status report on Gesneria pauciflora Urban. In Puerto Rican plant species of special concern: status and recommendations, Publicacion Cientifica Miscelanea No. 2." Department of Natural Resources, San Juan, Puerto Rico.
U.S. Fish and Wildlife Service. 7 March 1995. "Determination of Threatened Status for Gesneria pauciflora." Federal Register 44 (60): 12483-12487.