Delicate Clarkia [Clarkia delicata (Abrams) Nels. & MacBr.]

Delicate Clarkia [Clarkia delicata (Abrams) Nels. & MacBr.]

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

State/Federal. Status -- None ONAGRACEAE May-Jun.

Global Rank G2G3 State Rank S?

Distribution: San Diego County; Baja California, Mexico

Habitat: The periphery of oak woodlands and cismontane Chaparral haunts are the favored habitats for this annual. Soils at the Black Mountain-Lusardi site are mapped as Bancas stony loam; the population here was situated primarily on very old roadcuts in partial shade. Locales where observed were partially shaded by tree canopy or large shrubs, and typically were vernally mesic situations with substantial peripheral annual and herbaceous spring growth.

Known Sites: Delicate Clarkia was seen growing in a canyon north of Highway 94 east of Dulzura. This is a striking little Clarkia rarely seen in the back country; it is difficult at present to assess its rarity; it is best identified during a narrow flowering period from approximately April 23 to June 13 (dates based on herbarium collections). Old collections at the San Diego Natural History Museum are from the following locales: Mother Grundy Truck Trail, Black Canyon Road 5 miles south of Mesa Grande, a south slope near Honey Springs Road west of Bratton Valley, east end of Lyons Valley, south fork of Featherstone Creek, at Foster (now submerged by San Vicente Reservoir), Corte Madera, a burn in Harbison Canyon, south side of Moreno Reservoir, east side of Highland Valley Road southeast of Highway 67, 6 miles east of Lake Hodges Bridge, and a slope near the southern arm of El Capitan Reservoir. It is reported from near Orinoco Creek. Some of these historical sites are likely no longer extant, and are mentioned merely to indicate the geographical range within which the species may still occur. An unconfirmed recent report of a large population comes from eastern slopes of the Jamul Mountains. A small population was found on roadcuts near the intersection of Black Mountain Road/Lusardi and the connecting truck trail to Lake Sutherland. Another small population was found south of Deerhorn Valley Road in an Engelmann Oak Woodland. Old biological survey reports, possibly misidentified and referable to other species of Clarkia, note this species near Vista Romero Road near San Vicente Valley, near the community of Palomar Mountain, 1 mile west of Potrero Road near Highway 94, near the Sequan Truck Trail, and in the vicinity of Eagle Rock Road and Pine Hills near Orinoco Gorge and Paine Bottom Gorge.

Only six Baja specimens are found at the San Diego Herbarium; south to 32 5' North where collected by Moran (SD 127478) 2 km east of La Mision de San Miguel, Valle Ojos Negros.

Status: Delicate Clarkia populations are presently stable in San Diego County, given the relatively broad range within which it has been reported. In the 1990's a number of residential projects in cismontane oak savannahs and open mixed chaparral habitats are likely to endanger some back country populations of this inconspicuous annual. It should be noted that a plant census out of season could easily miss this species; late fall, winter, and early spring censusing for this clarkia is of dubius value. Clarkia delicata is quite distinct while alive and in flower; however, few botanists may be thoroughly familiar with its diagnostic traits which include spatulate rose petals and bicolored anthers which are bright orange-red on the tips. Significant portions of sizeable populations of Delicate Clarkia should be protected.

Copyright May 1994 Craig H. Reiser.

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