Dunn's Mariposa Lily [Calochortus dunnii Purdy]
Listing CNPS List 1B R-E-D Code 2-2-2
State/Federal. Status -- CR/C2 LILIACEAE May-Jun.
Global Rank G2 State Rank S2.1
Distribution: San Diego County; Baja California, Mexico
Habitat: Rocky openings in chaparral or grassland/chaparral ecotone are the preferred habitat of this species. In the Cuyamaca Mountains this bulbous perennial was observed in openings in Chamise on Boomer stony loam. San Miguel-Exchequer rocky silt loams are utilized on San Miguel Mountain in an arid chaparral with stunted Ceanothus tomentosus. Dunn's Mariposa Lily seems restricted to metavolcanic and gabbroic derived soils. At San Miguel Mountain it did not flower well during a year with poor rainfall.
Known Sites: This bulb is uncommon on San Miguel Mountain and on the western face of the Jamul Mountains; an unusual disjunct population occurs at Inspiration Point in the Cuyamaca Mountains. Old reports are from the Minnewawa Truck Trail on Otay Mountain extending to higher elevations such as at Doghouse Junction and near the transmitting station at the summit, on East Mesa in the Cuyamaca Mountains, on a southern slope of Cuyamaca Peak, near the south fork of Featherstone Creek, and on Guatay Peak. A very old report by K. Brandegee reports this bulb 2 miles from Descanso on the west side of the road on a rocky, brushy hillside. This locale may correlate with Guatay Mountain which has appropriate geology and soils for the species. Data Base reports are from Japacha Peak, 0.9 mile southeast of Oakzanita Peak, and the southern summit of Tecate Peak; a report from Lower Doane Valley is questionable; a number of Data Base reports reflect the same extended population near Inspiration Point.
No specimens of Dunn's Mariposa Lily from Baja California are located in the San Diego Natural History Museum's herbarium. Unconfirmed reports are from near Guadalupe Mountain, as well as Laguna Hansen.
Status: Existing populations of Dunn's Mariposa Lily are presently stable in San Diego County. All populations should be protected.
Copyright © May 1994 Craig H. Reiser.