California Adder's Tongue Fern [Ophioglossum californicum Prantl]

California Adder's Tongue Fern [Ophioglossum californicum Prantl]

Listing CNPS List 4 R-E-D Code 1-2-2

State/Federal. Status -- /C3c OPHIOGLOSSACEAE Dec.-May

Global Rank G4G5 State Rank S3?

Distribution: Amador County, Butte County, Merced County, Mariposa County, Monterey County, Stanislaus County, Tuolumne County; disjunct to San Diego County, San Bernardino County, Orange County; and Baja California, Mexico.

Habitat: The periphery of vernal pools, seeps, and vernally moist locales are favored by this primitive fern. On Mira Mesa this plant is found in an unusual, very open Chamise Chaparral (Redding cobbly loam), on flatlands which have mesic conditions for only a brief period in the spring. Olivenhain cobbly loam is mapped for the Proctor Valley road site, at the edge of a vernal pool.

Known Sites: A small colony was seen on a vernally moist slope supporting Highway 67 near Iron Mountain. Several dozen were noted growing on the fringe of a vernal pool alongside Proctor Valley Road at the 600 foot contour. It was common on a vernally moist hilltop north of Escondido Creek in Olivenhain. A sizeable population was reported on hills north and south of Questhaven Road near the intersection with Elfin Forest Road. It is growing in swales north of Poggi Canyon, on Carmel Mountain, and near incipient vernal pools southwest of the intersection of Highway 54 and Interstate 15. The latter site may soon be extirpated by development. It is scattered in chaparral openings on Miramar Air Station east of Interstate 805 and south of Miramar Road; a small colony was found in open stands of Chamise on the southwestern portion of Carmel Mountain. A very large population covering acres was recently reported from Proctor Valley. A recent report comes from the south side of Lower Otay Lake. Herbarium collections at San Diego's Museum of Natural History include specimens collected south of Poway Grade, on Point Loma above Loma Portal, the southeast end of Lee Valley, at Lake Murray, the northeastern slope of El Cajon Mountain, Camp Kearny, Mount Soledad, a hill west of Felicita Park, and near the corner of Balour and Encinitas Drive in Encinitas. Old biological survey reports note sites near Sundance Avenue and Carmel Mountain Road, west of Valley Center Road and south of Banbury Drive, in Carroll Canyon east of El Camino Memorial Park, a west facing slope above Honey Springs Road on Honey Springs Ranch, on Goat Peak north of Beeler Canyon in Poway, on the east slope of Bottle Peak near Lake Wohlford, and on the east side of Genesee Avenue and bounded by Miramar Road and La Jolla Village Drive and Regents Road. Reported by Roberts from Orange County at Temple Hill in Blue Bird Canyon near Laguna Beach.

Seen by C. Reiser in Aesculus parryi dominated chaparral at Jatay in Baja California; no specimens are currently found in the herbarium at the San Diego Natural History Museum for Baja California.

Status: California Adder's Tongue Fern is declining in San Diego County. Populations are typically quite small and growth is triggered by the slightest rainfall. As a result, this cryptic species is often difficult to find at known sites during extended periods without rainfall. Censusing for this fern is best done only following recent substantial rainfall. Given its apparent rarity in Southern California, substantial portions of sizeable populations are recommended for protection.

Copyright May 1994 Craig H. Reiser.

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