Large-leaved Filaree [Erodium macrophyllum H. & A.]

Large-leaved Filaree [Erodium macrophyllum H. & A.]

Listing CNPS Unlisted R-E-D Code None

State/Federal. Status -- None GERANIACEAE Mar.-May

Global Rank None State Rank None

Distribution: San Diego County, Riverside County, Los Angeles County, Alameda County, Contra Costa County, Colusa County, Fremont County, Glenn County, Kings County, Kern County, Merced County, Monterey County, San Benito County, Santa Cruz County, San Joaquin County, San Luis Obispo County, San Mateo County, Santa Cruz Island, Solano County, Sonoma County, Stanislaus County, Tehama County, Yolo County; Utah; Baja California, Mexico

Habitat: This annual typically grows in Valley and Foothill Grasslands in open habitat on friable clay soils.

Known Sites: In San Diego County this small herb grows on cracked clay soils on a mesa on the northern flanks of Otay Valley, east of Rock Mountain. It is reported from near El Capitan Dam, and near an old cement factory quarry on the Jamul Ranch near the Otay Lakes. Boyd reports this species in western Riverside County to the south of Lake Mathews, as well as on the south flank of Alberhill Mountain. Smith reports this filaree in the Santa Barbara region as scattered on grassy flats on serpentine on the west slopes of Figueroa Mountain, on a hillside east of Black Willow Spring near Montgomery potrero, and on Santa Cruz Island. Hoover reports this species as frequent on open hillsides in the interior of San Luis Obispo County on friable, calcareous or gypseous clay soils. Twisselmann reports Large-leaf Filaree as occasional in the Temblor Range, near Tehachapi, at Mexican Mine in the extreme southwestern Tehachapi Mountains along the northwest side of Antelope Valley, and at Dry Bog Knoll at the head of Adobe Canyon in the Greenhorn Mountains. Thomas reports this annual as rare in the Santa Cruz Mountains near Pescadero.

One herbarium specimen from Baja California is at the San Diego Museum of Natural History at 30 42' North in Arroyo de la Escopeta where it was collected by Moran (SD 91524). It was also observed growing on the periphery of the vernal pools at Valle de las Palmas.

Status: This small annual is apparently well distributed in central and northern California, but is very rare in Southern California. Large-leaved Filaree is presumed to be declining in Southern California due to loss of its friable clay microhabitat. All populations in Southern California are recommended for protection despite the sizeable populations to the north. Oftentimes, the distinctive clay soils where this species can occur, include other sensitive species such as Convolvulus simulans. The very crumbly clay soil is itself quite rare in the region and undoubtedly accounts for the rarity of several species restricted to this substrate.

Copyright May 1994 Craig H. Reiser.

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