Verity's Dudleya

Dudleya verityi

Description

Dudleya verityi (Verity's dudleya) is unique among Dudleya taxa in this rule in that it forms multiple rosettes, as many as 100 to a colony. Rosette leaves are 0.8-2 in (2-5 cm) long and 0.2-0.4 in (0.5-1 cm) wide, floral stems are 2-5.9 in (5-15 cm) tall, and corollas are lemon-yellow with petal tips re-curved up to 90 degrees. One scientist distinguished D. verityi from D. caespitosa by its much shorter leaves and flowering stems. He separated D. verityi from D. cymosa ssp. ovatifolia by its more elongated caudex, multiple dichotomously branched rosettes, and paler flowers.

D. verityi was originally collected in 1944 and treated as D. caespitosa; in 1966, Peter Raven and Henry Thompson treated it as D. farinosa, and it was finally described as D. verityi in 1983.

Habitat

Verity's dudleya occurs exclusively on the out-crops and soils derived from the Miocene Conejo volcanics at the western end of the Simi Hills and the Santa Monica Mountains. Most of the coastal sage scrub where D. verityi occurs is dominated by coastal sagebrush (Artemisia californica ), wild buckwheat (Eriogonum fasciculatum ), purple sage (Salvialeucophylla ), and occasionally giant coreopsis (Coreopsis gigantea ). Verity's dudleya is associated with the rare Conejo buckwheat (Eriogonum crocatum ) and Blochman's dudleya (Dudleya blochmaniae ssp. blochmaniae ). A unique lichen flora of more than 70 species is associated with D. verityi and coastal sage scrub habitat on Conejo Mountain.

Distribution

Verity's dudleya is limited to three populations occurring in a narrow band 4 mi (6 km) in length along the lower slopes of Conejo Mountain, from Long Grade Canyon to U.S. highway 101. The northernmost population consists of over a thousand individuals and another is considered abundant in the limited habitat it occupies.

Threats

Verity's dudleya survives on cliff habitats at the base of the Conejo Grade on land zoned for mineral extraction. The lower slopes of Conejo Mountain have historically been the site for quarrying of construction-grade rock, and there are abandoned, active, and proposed quarry operations within the distribution of D. verityi. These extraction activities pose a threat to this taxon. The majority of the distribution of D. verityi is privately owned in a region with rapidly increasing development. Only a small portion of habitat is owned by a public agency, the Ventura County Flood Control District.

Niebla ceruchoides, a small cushion lichen that apparently functions as a nursery for seedling establishment of Verity's dudleya, has been damaged by air pollution in its coastal sage habitats. Air Pollution, along with habitat loss, is reducing Niebla occurrences on Conejo Mountain, the largest population on the mainland of California.

Conservation and Recovery

Only a small portion of the critical habitat of the Verity's dudleya is owned by a public agency, the Ventura County Flood Control District. This habitat must be strictly protected from threatening activities. Most of the critical habitat of this rare plant is privately owned, and is threatened, by quarrying and other destructive activities. These critical habitats should also be protected. This could be done by acquiring the habitats and establishing ecological reserves, or by negotiating conservation easements with the landowners. The populations of the Verity's dudleya should be monitored, and research undertaken into its ecological needs. Studies should be made of the possibility of fostering the recovery of the rare plant in abandoned quarries within its habitat area.

Contacts

U.S. Fish and Wildlife Service
Ventura Field Office
2493 Portola Road, Suite B
Ventura, California 93003
Telephone: (805) 644-1766
Fax: (805) 644-3458

U. S. Fish and Wildlife Service
Regional Office, Division of Endangered Species
Eastside Federal Building
911 N. E. 11th Ave.
Portland, Oregon 97232-4181
Telephone: (503) 231-6121
http://pacific.fws.gov/

Reference

U.S. Fish and Wildlife Service. 29 January 1997. "Endangered and Threatened Wildlife and Plants; Determination of Endangered Status for Two Plants and Threatened Status for Four Plants From Southern California." Federal Register 62(19): 4172-4183.