Mountain Springs Bush Lupine [Lupinus excubitus Jones var. medius (Jepson) Munz]

Mountain Springs Bush Lupine [Lupinus excubitus Jones var. medius (Jepson) Munz]

Listing CNPS List 1B R-E-D Code 2-1-3

State/Federal. Status -- /C2 FABACEAE Mar.-Apr.

Global Rank G3T2 State Rank S2.2

Distribution: San Diego County and Imperial County; Baja California, Mexico

Habitat: Pinyon Juniper Woodland and Sonoran Desert Scrub at higher elevations are utilized by this herbaceous shrub. Rositas loamy coarse sand is the soil type mapped for some colonies of this bush lupine near Jacumba. Alluvial sandy washes on the periphery of stream channels may be a preferred microhabitat. Generally, this lupine grows in the open, unencumbered by woodier shrubs.

Known Sites: This lupine is rare at In-Koh-Pah County Park and nearby Myers Creek. It is fairly common along the trail to Smugglers Cave and southward a few plants were seen just across the Mexican border into the Sierra Juarez Mountains. Old reports from nearby locales include McCain Valley, Carrizo Gorge, Canebrake Canyon, and Table Mountain. Herbarium specimens are from Dos Cabezas, east of Monument Peak, east of the Sawtooth Mountains and south of Inner Pasture, and in the In-Koh-Pah Mountains south of Rockhouse Canyon. Data Base reports are from lower Storm Canyon, in Vallecito Valley near the mouth of Storm Canyon, the south edge of Vallecito Valley west of The Potrero, several locales in The Potrero, several locales in Inner Pasture north of the summit of Red Top Mountain, at a number of sites in Canebrake Wash and near the Pepperwood Jeep Trail, in Rockhouse Canyon both east and west of the rockhouse structure, in McCain Valley 0.3 mile north of the junction of McCain Valley Road and the road to Lost Valley, other nearby locales in McCain Valley, at various locales north and west of Table Mountain, 1.65 miles due east of confluence of Tule Creek and Carrizo Gorge, southeast of Table Mountain near both the Mica Gem Mine and the Mira Gem Mine, south of Table Mountain and immediately north of Old Highway 80, in Jacumba Jim Canyon; also in Imperial County in Myer Valley.

Six specimens from Baja California are found at the herbarium for the San Diego Natural History Museum; south to 29 19' North where collected by Moran (SD 54574) on a granitic ridge northwest of Cerro San Luis.

Status: The deep, blue flowers of Mountain Springs Bush Lupine are superficially distinct from typical L. excubitus; moreover, the habitat -- desert mountain washes -- is very different. The populations in San Diego County are presently stable, owing to limited development of its high desert habitat. All populations should be protected.

Copyright May 1994 Craig H. Reiser.

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