San Diego Button-celery

Eryngium aristulatum var. parishii

Description

San Diego button-celery, Eryngium aristulatum var. parishii, is a member of the parsley family. It blooms from May through June and is usually an annual. However, under favorable conditions it facultatively becomes a perennial herb with a perennial tap root. The plant has spreading or ascending shape and reaches a height of 16 in (40.6 cm). The stems and lanceolate leaves are gray green with spinose lobes giving the plant a prickly appearance. Inflorescences form on short stalks with few-flowered greenish heads on the ends of branches. Its greenish heads, fruits with unequal scales, and bractlets without calloused margins separate it from other varieties.

E. aristulatum var. parishii is separated from E. aristulatum var. aristulatum by having styles in fruit that are about the same length as the calyx (outer whorl of protective leaves around the flower) and is separated from E. aristulatum var. hooveri by having bractlets (modified leaves) without callused margins). A population of Eryngium was found in 1997 on Marine Corps Base Camp Pendleton (MCB Camp Pendleton) that is diagnosable as and may represent a new species.

Habitat

The species occurs in vernal pools which form in areas with Mediterranean climates where slight depressions become seasonally wet or inundated following fall and winter rains. Water remains in these pools for a few months at a time, due to an impervious layer such as hard pan, clay, or basalt beneath the soil surface. Gradual drying occurs during the spring. The pools form on mesa tops or valley floors and are interspersed among very low hills usually referred to as mima mounds.

Distribution

The species once occurred from Riverside County, California, south to northern Baja California, Mexico.

San Diego button-celery ranges from as far north as the Santa Rosa Plateau, Riverside County, south to the mesas north of Ensenada, Mesa de Colonet, and San Quintin, Baja Califomia, Mexico. San Diego button-celery is found in pools on Del Mar Mesa, Mira Mesa, Kearny Mesa, Marine Corps Air Station Miramar (MCAS Miramar), MCB Camp Pendleton, and at sites within the cities of Tierrasanta, San Marcos, Carlsbad, and Ramona; it was extirpated from a site in the city of La Jolla. San Diego button-celery is also found in the southern portion of San Diego County on Otay Mesa, near the Lower Otay Reservoir and in Proctor Valley. It also was found near the Tijuana Airport, but is believed to be extirpated at this locale. There are no known herbarium collections of San Diego button-celery from Normal Heights near San Diego State University.

Threats

The habitat and range of this species have been greatly reduced. Vernal pools, existing as slight depressions on flat mesas, are found in locations that are especially vulnerable to one or more of the following habitat disturbances: urban and agricultural development, off-road vehicle use, cattle trampling, human trampling, road development, military activities, and water management activities. Many pool groups were entirely eliminated and replaced with urban or agricultural developments.

Conservation and Recovery

Conservation of the San Diego button celery requires that its remaining vernal-pool critical habitats be protected from conversion to urbanized or agricultural land-uses. The damaging effects of off-road vehicles, livestock grazing, trampling, and habitat changes by non-native plants must also be decreased or eliminated. Several of its populations occur on federal lands in Miramar Naval Station and Camp Pendleton, and these sites should be rigorously protected. Other populations are on private land and are vulnerable to destruction or disturbance. These sites should be protected by acquiring the critical habitat and designating ecological reserves, or by negotiating conservation easements with the landowners. Binational attention should also be paid to the protection of critical habitats in Baja California, Mexico. The surviving populations of the San Diego button celery should be monitored, and searches made to try to discover additional ones (including in Baja California). Research should be undertaken into the biology and habitat needs of this endangered plant, and into management practices that would enhance its populations.

Contacts

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

Sacramento Ecological Services Field Office
Room E-1803/1823
2800 Cottage Way
Sacramento, California 98525
Telephone: (916) 978-4866
Fax: (916) 978-4613

Ventura Ecological Services Field Office
Suite 100, 2140 Eastman Avenue
Ventura, California 93003
Telephone: (805) 644-1766
Fax: (818) 904-6288

References

U. S. Fish and Wildlife Service. 3 August 1993. "Endangered and Threatened Wildlife and Plants; Endangered Status for Three Vernal Pool Plants and the Riverside Fairy Shrimp." Federal Register 58 (147): 41384-41392.

U. S. Fish and Wildlife Service. 1998. "Recovery Plan for Vernal Pools of Southern California." U. S. Fish and Wildlife Service. Portland. 160 pp.