San Clemente Island Woodland-star

Lithophragma maximum

Description

Lithophragma maximum is a member of the saxifrage family (Saxifragaceae) which flowers from April to June. It is a rhizomatous, perennial herb with basal leaves and two or three stout flowering stems from 16 to 24 in (40 to 60 cm) high. Each flower-bearing stem produces 20 or more white, campanulate (bell-shaped) flowers, each about 0.5 in (12 mm) length. The leaves are palmately compound and arise from the base on slender petioles 6 in (15 cm) long. Lithophragma maximum is differentiated from other species of Lithophragma by its trifoliolate compound leaves.

Lithophragma maximum was originally described by Rimo Bacigalupi in 1963 as L. maxima from a collection made in 1936 on San Clemente Island by Mrs. Nell Murbarger. The specific epithet was later corrected to L. maximum by Bacigalupi in 1979. At the time a monograph was published of the genus in 1965 the author was unaware of L. maximum ; however, L. maximum has been recognized in 1968, 1974, and 1993.

Habitat

San Clemente Island woodland-star is found on grassy seats in canyons and in rock crevices within coastal bluff scrub on the southeastern part of San Clemente Island, whose terrain is marked by a broad, high plateau surrounded by deeply incised cliffs. Lithophragma maximum occasionally occurs with Castilleja grisea (San Clemente Island paintbrush), but there is no consistent pattern of distribution.

Distribution

Lithophragma maximum was thought to be extinct until it was rediscovered in 1979 in Bryce and Eagle Canyons by Mitch Beauchamp and Howard Ferguson. The number of plants on the island found in Bryce Canyon has fluctuated from five to 15 individuals since its rediscovery. Three of the 15 plants originally discovered in Eagle Canyon are believed to be extant at this time. Sixteen additional plants were found in Near Death Canyon in 1991. There are currently only 11 known populations, all from the southeastern part of the island in deeply incised canyons. Approximately 200 plants were located in the spring of 1996 during field surveys for this species. These plants were generally found at or near previously known sites.

Threats

Lithophragma maximum is threatened by destruction and degradation of habitat, erosion, competition with exotic plant species, and fire.

Lithophragma maximum is thought to have existed on the plateau area of San Clemente Island before the introduction of non-native grasses. The remaining habitat of L. maximum persists only within steep canyons. Erosion threatens not only the individual plants but the entire habitat that supports them. During the winter of 1979-1980, large portions of canyon walls were observed to have sloughed taking large numbers of endemic plants with them, including individuals of this taxon. The erosion in and around these steep canyons is exacerbated by fire that further destroys the already depleted groundcover.

Conservation and Recovery

The San Clemente Island woodland-star survives only in about 11 perilously small populations, totaling about 200 plants. Although this endangered plant occurs on land owned and conserved by the federal government, it is still threatened by competition with invasive alien plants, and by fires associated with military activities (ship-to-shore artillery practice). The protection of this endangered plant requires a strict regime of fire prevention, and management to reduce or eradicate the threatening alien plants. The populations of the San Clemente Island woodland-star should be monitored, and research undertaken into its basic biology and ecological requirements. It should be propagated in captivity, to produce stock for out-planting to supplement the tiny wild population.

Contact

U.S. Fish and Wildlife Service
Carlsbad Field Office
2730 Loker Avenue West
Carlsbad, California 92008-6603
Telephone: (760) 431-9440
Fax: (760) 431-9624

Reference

U.S. Fish and Wildlife Service. 8 August 1997. "Endangered and Threatened Wildlife and Plants; Determination of Endangered Status for Three Plants from the Channel Islands of Southern California." Federal Register 62 (153): 42692-42702.