Indian Valley Bush Mallow [Malacothamnus aboriginum (Rob.) Greene]

Indian Valley Bush Mallow [Malacothamnus aboriginum (Rob.) Greene]

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

State/Federal. Status -- None MALVACEAE Apr.-Oct.

Global Rank G2G3 State Rank S2S3

Distribution: San Diego County, Fresno County, Monterey County, San Benito County

Habitat: Montane Chaparral and lower Montane Coniferous Forest are the preferred habitats of this herbaceous shrub. At the few known sites in San Diego County, Indian Valley Bush Mallow exhibits a tendency to grow in minor rocky outcrops within a relatively diverse chaparral flora. Sheephead rocky fine sandy loam is mapped for the Mount Laguna site.

Known Sites: Several dozen vigorous plants grow just north of the San Diego State Astronomical Observatory on a rocky knoll. A patchy colony at Garnet Peak is surrounded by planted pines. Two other colonies are reported nearby. The population at the old tracking station on the peak at Mount Laguna is extirpated. There is an unconfirmed report from Black Mountain-Lusardi. Similar plants from distant southern San Benito County, eastern Monterey County, and western Fresno County are reported in the Jepson Manual (1993) as this species.

Status: In San Diego County this shrub is declining and close to extirpation. The small population on Garnet Peak has been unnecessarily surrounded by individual shrub fences causing major site disturbance; planted pines are now "shading-out" this colony. Genetic affinity with the populations far to the north near San Benito should be investigated to determine if this is an unusual disjunction, or rather if separate subspecies/ species status is warranted. If the latter, this entity deserves a 3-3-3 R-E-D Code. All populations should be protected.


Copyright May 1994 Craig H. Reiser.

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