Palo de Rosa

Ottoschulzia rhodoxylon

Description

A small evergreen tree, Palo de Rosa (Ottoschulzia rhodoxylon ) reaches 12-15 ft (3.7-4.6 m) in height. Its distinctively reddish heartwood is suitable for turnery articles. Tree leaves are alternate and smooth with an elliptic to ovate shape. At their apex, these leaves are rounded or blunt, and at their base, they are entire, thick, and leathery. Palo de Rosa flowers are bisexual and are arranged singly or in clusters at the leaf bases. The flower's corolla is tubular and has five lobes. The fruit is a drupe with a thin covering. Flowers and fruit seem to be produced irregularly. As yet, no seedlings have been observed.

Habitat

Different types of habitat exist at each of the three locations. The north coast, Bayamón site is situated in a semievergreen, seasonal forest at an elevation of 325 ft (100 m). In the southwestern coast Guánica Forest, the species occurs in a low elevation, semi-deciduous, dry forest on limestone. One tree in this population is located alongside a dry stream bed which carries water only during torrential rains. The individual in the Maricao Forest survives in a lower montane, semievergreen forest on serpentine out-crops. This location is at an elevation of about 1,960 ft (600 m).

Distribution

Only nine individuals are known to exist in Puerto Rico, and the species is also rare in the Dominican Republic. In Puerto Rico, the species survives in three locations. One site is located in the north coast limestone Hills of Bayamón, and several sites are found within the dry limestone Guánica Commonwealth Forest on the south coast. A single individual has been reported in the Maricao Commonwealth Forest.

Threats

Always rare, this species is further endangered by deforestation for industrialization and residential development. The Bayamón population is west of San Juan, a rapidly developing urban area. In addition, many of Puerto Rico's remaining forests, including all Palo de Rosa sites, are second-growth. The surviving individuals in the Guánica Forest are in danger because they are located near dry stream beds and roadsides which could potentially be altered by forest management practices or flash floods. Palo de Rosa also flowers and fruits irregularly, and seedlings have never been observed.

Conservation and Recovery

Palo de Rosa should be placed on the commonwealth list of endangered and threatened species. At all three population sites, management decisions and efforts should be made to protect the species.

Contacts

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

U. S. Fish and Wildlife Service
Boquerón Ecological Services Field Office
P. O. Box 491
Boquerón, Puerto Rico 00622-0491
Telephone: (787) 851-7297
Fax: (787) 851-7440

References

Ayensu, E. S., and R. A. Defilipps. 1978. Endangered and Threatened Plants of the United States. Smithsonian Institution and World Wildlife Fund, Washington, D.C. 403 p.

Liogier, H. A., and L. F. Martorell. 1982. Flora of Puerto Rico and Adjacent Islands: A Systematic Synopsis. University of Puerto Rico, Río Piedras, P.R. 342 pp.

Little, E. L., Jr., R. O. Woodbury, and F. H. Wadsworth. 1974. Trees of Puerto Rico and the Virgin Islands, 2nd vol. U. S. Department of Agriculture, U. S. Forest Service. Agriculture handbook no. 449.

U. S. Fish and Wildlife Service. 10 April 1990. "Determination of Endangered Status for Ottoschulzia rhodoxylon (Palo de Rosa)." Federal Register 55 (69): 13488-13491.