San Diego Golden Star [Muilla clevelandii (Wats.) Hoover]
Listing List 1B R-E-D Code 2-2-2
State/Federal. Status -- /C2 ALLIACEAE Apr.-May
Global Rank G2 State Rank S2.1
Distribution: San Diego County; Baja California, Mexico
Habitat: Valley Grasslands, particularly near Mima Mound topography or the vicinity of vernal pools, are the preferred habitat of this perennial corm. This plant does not grow with woody perennials; it frequently is found with fields of Nassella pulchra, a common bunchgrass, and Sisyrinchium bellum. Redding Cobbly loams are mapped for locations near Miramar, while Stockpen gravelly clay loam is found with the populations on northeastern Otay Mesa. Given the dearth of shrubs associated with Muilla, clay soils with good shrink/swell potential are obviously preferred.
Known Sites: This corm grows near vernal pools on Otay Mesa north of the Donovan Prison. It is scattered at sites near the Miramar Mounds and on Miramar Air Station south of the eastern terminus of Eastgate Mall. Scattered populations occur around Lower Otay Lake, such as at the east end near the Daley Rock Quarry. Major populations covering many acres were recently reported from Proctor Valley, as well as by Escondido Creek near Via de las Flores. A small population is found alongside the Sweetwater River upstream of the Sweetwater Reservoir and just north of the old wooden bridge. Numerous reports where possibly still extant include 0.5 mile west of San Dieguito Reservoir, Lopez Canyon, Mission Trails Park, a mesa south of Los Peñasquitos Canyon, Murphy Canyon, 0.5 mile southwest of Santana High School in north Santee, the west slope of San Miguel Mountain, and at the Kuebler Ranch on eastern Otay Mesa. Herbarium specimens include Foster (San Vicente Reservoir) and a locale at Rancho Santa Fe. Data Base reports are for the south end of Santo Road near Murphy Canyon, just north of Shepherd Canyon and west of Mission Trail Regional Park, 0.8 mile north of Mission Dam, a ridge north of Fortuna Mountain, Little Sycamore Canyon, mesa south of San Diego State College [likely extirpated], both east and south of the Miramar Naval Air Station runways, west of Highway 163 between San Clemente Canyon and Clairemont Mesa Boulevard, in Mission Hills [possibly extirpated], the old Brown Field Bombing Range, near the Otay Mountain Truck Trail, the eastern edge of Otay Mountain 1 mile north of the Mexican border, the western edge of Otay Mountain both 0.5 and 1.25 miles north of the Mexican border, Little Cedar Canyon on Otay Mountain, between the San Diego River and Mast Boulevard 1000 feet east of Cuyamaca Street in Santee, a mesa between Black Mountain Road and Interstate 15 south of Peñasquitos Canyon, north of Little Sycamore Canyon on a ridge 0.25 mile east of Quail Canyon, near 50th Street and Adams in San Diego [likely extirpated], 0.5 mile south of the Lower Otay Reservoir camping area, north of San Clemente Canyon between the sand mining pit and Highway 163, the vicinity of Highway 163 and Kearney Villa Road, south and east of the Miramar Naval Air Station runways, the west gate of this air station, 2.5 miles south of Alpine on the Sky Mesa Ranch near South Grade Road, west of Wolf Canyon near Otay Valley, west of La Media Road 1.5 miles south of Brown Field, west of Sycamore Canyon and a jeep trail, 0.7-1.1 miles south of the junction of Highway 94 and Honey Springs Road, Cedar Canyon on Otay Mountain, Minnewawa Truck Trail about 0.5 mile south of Otay Lakes Road, both east and west of Little Cedar Canyon, Chollas Heights Naval Radio Station, southeast of Black Mountain Road near the 4-S Ranch, several locales north of the tip of Upper Otay Reservoir, the east side of the Otay Reservoirs between the upper and lower lakes, southeast of San Marcos Creek Canyon approximately 1.75 miles southwest of Lake San Marcos Dam, southeast of Rancho Santa Fe Road on both side of an intermittent watercourse approximately 2.2 miles southwest of Lake San Marcos, and 1.3 miles north of Otay Lakes Road and west of Jamul Creek. A number of the Data Base reports represent peripheral colonies of a single larger population; hence fewer populations are recorded than may be apparent.
Only three collections from Baja California are found at the San Diego herbarium; south to 32 22' North where collected by Moran (SD 102127) on the south side of Valle de las Palmas.
Status: San Diego Golden Star is severely declining with urban expansion of the City of San Diego and outlying cities and communities. Muilla clevelandii will be heavily impacted in the 1990's by continued urban expansion. The large Proctor Valley populations are endangered by proposed Otay Ranch development, and expected severe potential secondary impacts from an influx of humans into this still lightly utilized area. Currently this species is not being adequately protected, and a number of development sites with good potential for occurrence are not being adequately censused in the spring; it is extremely difficult to identify except when in flower during this period. During years of poor rainfall, as with the late 1980's, this corm may not flower, or deceptively bloom in only limited numbers. Apparent rarity in Baja California should be factored into any analysis of the level of endangerment for this species. Populations have undoubtedly declined substantially within the last two decades, along with the loss of peripheral vernal pool habitat. The broadened filament base of San Diego Golden Star should be carefully examined as Bloomeria crocea is superficially quite similar and much more common in San Diego County. As a result, it may be that populations of Muilla clevelandii are being overlooked. Habitat of both is sometimes similar. All substantial populations should be protected; significant portions of smaller populations should also be protected.
Copyright © May 1994 Craig H. Reiser.
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