Rush-like Bristleweed [Machaeranthera juncea (Greene) Shinners = Haplopappus junceus Greene]

Rush-like Bristleweed [Machaeranthera juncea (Greene) Shinners = Haplopappus junceus Greene]

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

State/Federal. Status -- None ASTERACEAE Jun.-Oct.

Global Rank G4 State Rank S3.2

Distribution: San Diego County; Baja California, Mexico

Habitat: A xeric, low-growing Chamise Chaparral or Diegan Sage Scrub is the preferred habitat of this inconspicuous subshrub. Acid Igneous rock lands are found at the Santee locale. Usually Rush-like Bristleweed grows in exposed locales with rocky substrate that does not foster much annual understory. This is an inconspicuous species which flowers late and is probably under-reported.

Known Sites: Bristleweed is found in chaparral along Highway 94 near Jamul, and in similar habitat off Montanya Drive near Lilac Road. It Grows with some abundance on steep chaparral slopes in Lee Valley and is rare in similar habitats in nearby Rancho Jamul, north of Chocolate Summit Road in Alpine, and north of Bermuda Lane in El Cajon. Typically, only small numbers of this species are found at any single site. Much of the potential habitat occurs in inland chaparral areas of San Diego County which have not been thoroughly investigated. Over 100 plants were seen on a rocky hillside in Santee east of Magnolia Drive in 1990. It grows along disturbed trails at Swartz County Regional Park, and is occasional on the south flanks of Viejas Mountain, near Poway Grade not far from its intersection with Highway 67, in the rugged hills south of Japatul Valley Road, and north of the freeway in Alpine. Several plants were seen in chaparral plains east of Pala. Old reports are from Twin Peaks in Poway and far southeast to Potrero. Numerous old biological survey reports note this species at Sequan Truck Trail, Dye Road in Ramona, Peutz Valley Road near Interstate 8, San Vicente Creek West of Wildcat Canyon Road, Silva Road near Flinn Springs, Steele Canyon, south of Japatul Road and west of the junction with Lyons Valley Road, Highway 94 just west of Jamul, south of Interstate 8 adjacent to Flinn Springs County Park, south of Oak Creek Road near Lake Jennings, both to the east and on the southwestern flanks of Starvation Mountain, northeast of Dorothea Terrace in Poway, 1 mile west of Campo near Highway 94, near Blossom Valley Road and Flinn Springs, west-facing slope above Honey Springs Road on Honey Springs Ranch, Hester Granite Pit on Willow Glen Road north of Oak Drive near Dehesa, north of Tavern Road and Interstate 8 in Alpine, near Poway Road southwest of Espola Road, south of Woods Valley Road on Bear Ridge 0.75 mile East of Valley Center Road, north of the junction of Highway 94 and Highway 188 at the turnoff to Tecate, the south side of Lyons Valley Road and Honey Springs Truck Trail, near Rangeland Road in Ramona, west of Anthony Road near Lilac, south of Peutz Valley, northwest of San Marcos' Palomar College, on The Mesa southeast of Singing Hills Country Club and west of Sloane Ranch, Willow Glen Road near Dehesa, near South Grade Road in Alpine, west of Harbison Canyon near Crest, near Goat Peak north of Beeler Canyon near Poway, north of Lilac Road and west of Anthony Road, south of Schoolhouse Canyon and east of Bandy Canyon, near Valley Center Road south of Rincon Springs, and near Old Coach Road in Poway south of Highland Valley Road.

Thirty-one collections from Baja California are found in the San Diego Herbarium. It ranges south to 30 44' North where it was collected by Moran (SD 91386) at the head of Arroyo San Simon.

Status: This shrub is slowly declining in San Diego County as urban expansion reaches into the foothill region. Numerous undiscovered populations likely exist for this species. Provisionally, it is recommended that substantial portions of sizeable populations be protected.


Copyright May 1994 Craig H. Reiser.

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