Thurber's Pilostyles [Pilostyles thurberi Gray]

Thurber's Pilostyles [Pilostyles thurberi Gray]

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

State/Federal. Status -- /C3c RAFFLESIACEAE January

Global Rank G3 State Rank S3.2

Distribution: San Diego County, Imperial County, Riverside County; Arizona; Nevada; Baja California and Sonora, Mexico

Habitat: Sonoran Desert Scrub flatlands (specifically as a parasitic species on Psorathamnus emoryi) are the general habitat of this little collected and cryptic species.

Known Sites: Thurber's Pilostyles was seen 4.5 miles west of the Imperial County Line on Highway S-2, near the power lines. Herbarium specimens examined were from the Carrizo Badlands, Egg Mountain, Canyon Sin Nombre, Fonts Point Wash, and in the Jacumba Mountains east of Carrizo Canyon. Data Base reports from San Diego County are from the Carrizo Badlands Overlook, behind the ranger station at Ocotillo Wells State Vehicular Recreation Area, 2 miles from Ocotillo Wells in this recreation area, and north of the Coyote Mountains and south of the Carrizo Badlands. Herbarium specimens from Imperial County are 0.6 mile south of San Felipe Creek and west of Highway 99 near the Salton Sea, between Coyote Mountain and U.S. Highway 80, 1.7 miles south of San Felipe Creek, at Mount Signal, in the Davies Valley, and 2 miles west of Plaster City on Highway 80; a specimen was also noted from Sonora, Mexico. Data Base reports from Imperial County note sites 0.6-0.7 mile south of San Felipe Creek west of the Salton Sea along Highway 86, 1000 yards north of Highway 78 and 2.3 miles west of Highway 86, along county road S-2 2 miles east of the San Diego County Line, 0.8 mile southeast of Kane Springs, in Pinto Wash on the Yuha Desert, at Tule Wash at both 2.0 and 2.75 miles east of the San Diego County line and 2 miles west of Plaster City along county road S-80, between San Felipe Creek and Tarantula Wash 2 miles north of Highway 78, 0.25 mile west of Mosca on the north side of the Superstition Mountains, less than 0.13 mile east of Mosca, in the Superstition Hills, 1 mile west southwest of Kane Spring, 1.5 miles southeast of Kane Spring, 1.5 miles southeast of Elmore Desert Ranch south of Highway 99, 6 miles northwest of Kane Spring and south of Highway 99, several locales east of the Superstition Mountains, 3.5 miles south of Dry Lake and 2.5 miles north of the gravel pit and north of Filaree Canal, 1 mile north of Superstition Mountain in the parachute test range, north of the naval reservation and 5 miles southeast of Superstition Mountain, the northeastern corner of Superstition Mountain Parachute Test Range, 5 miles southeast of Superstition Mountain, 2.5 miles southeast of Superstition Mountain, along the jeep trail at the head of Surprise Wash, and near Ocotillo between Coyote Mountain and U.S. Highway 80. Shreve and Wiggins report it from near the mouth of the Gila River in Yuma County, Arizona.

Status: Thurber's Pilostyles is presumed stable on the southern deserts, given the limited impacts to its relatively broad potential habitat. The status of this fleshy parasitic plant, which embeds itself in the stems of its host plant, is poorly known in San Diego County; more collection information is needed. This is a minute, cryptic species which may not superficially appear to be a flowering plant. Substantial portions of sizeable populations should be protected. This species likely occurs at many more locales than are reported; however, its cryptic nature allows it to be readily overlooked.

Copyright May 1994 Craig H. Reiser.

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