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Lyonia Truncata Var. Proctorii

Lyonia truncata var. proctorii

No Common Name

Status Endangered
Listed April 27, 1993
Family Ericaceae (Heath)
Description Evergreen shrub growing with small, white, urn-shaped flowers.
Habitat Semi-arid mountains of near-vertical slopes with the area dominated by broadleaf trees.
Threats Agricultural, rural, and tourist development.
Range Puerto Rico


Lyonia truncata var. proctorii is an evergreen shrub which may reach up to 6.6 ft (2 m) in height. The leaves are alternate, elliptic to ovate, coriaceous, and from 0.4-1.7 in (0.9-4.5 cm) long and 0.2-0.9 in (0.4-2.3 cm) wide. The leaf margins may be toothed and the lower surface is sparsely to moderately lepidote and moderately to densely pubescent. The inflorescences are fasciculate with from two to 15 flowers. Pedicels are from 0.1-0.2 in (2-5 mm) in length and sparsely pubescent. Flowers are small, 0.03-0.06 in (0.7-1.5 mm) in length, white, and urn-shaped. The fruit is a dry capsule, 0.1-0.2 in (3-4.5 mm) in length and 0.1-0.16 in (2.5-4 mm) in width, sparsely pubescent, and contains seeds approximately 0.1 in (2.5 mm) in length.

This shrub was discovered in September of 1987 by Dr. George Proctor and described by Dr. Walter Judd in 1990. It was observed reproducing during preliminary studies in the month of October 1993 and again in April and May of 1994. Only one or two plants have been observed to have seeds in the fruit.


L. truncata var. proctorii is endemic to Puerto Rico and known only from the very steep slopes of Cerro Mariquita in the range of hills known as the Sierra Bermeja in the municipality of Cabo Rojo. The site is located within the subtropical dry forest life zone. Average annual precipitation just to the west of the Sierra Bermeja at the Cabo Rojo National Wildlife Refuge is 34.8 in (883 mm) based on measurements from 1980-1993. The drier period extends from December through March and the wetter period includes May and September through November.


This species is usually found growing in the exposed sun. The population has been estimated at about 63 individuals; however, because the species is found on extremely steep slopes, this may be an underestimate.


Clearing of land for grazing has destroyed some habitat that may have been occupied by this species. In addition, fire in this dry southwestern range of hills is common, particularly during the drier months. Currently the species is only known from one locality; therefore, the risk of extinction is extremely high.

This species is currently being threatened by intense agricultural, rural, and tourist development. The land on which this species occurs is being cleared for grazing by cattle and goats. Adjacent land is being subdivided for sale in small farms, and tourist/urban developments. In the Sierra Bermeja, the population occurs on privately owned land, which has been subject to intense pressure for residential and tourist development. The Sierra Bermeja has also been considered in a copper and gold mining proposal.

Conservation and Recovery

Existing populations of this species should be protected through acquisition or conservation easements. Individual plants should be monitored as should introduced populations.


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
Telephone: (809) 851-7297
Fax: 809-851-7440


U.S. Fish and Wildlife Service. 1995. " Aristida chaseae, Lyonia truncata var. proctorii, and Vernonia proctorii Recovery Plan." U.S. Fish and Wildlife Service, Atlanta, Georgia. 21 pp.

U.S. Fish and Wildlife Service. 27 April 1993. "Endangered and Threatened Wildlife and Plants; Determination of Endangered or Threatened Status for Three Puerto Rican Plants." Federal Register 58 (79):75755-75758.

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