San Diego Ambrosia [Ambrosia pumila (Nutt. Gray]

San Diego Ambrosia [Ambrosia pumila (Nutt. Gray]

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

State/Federal. Status -- /C2 ASTERACEAE Jun.-Sep.

Global Rank G3 State Rank S2.1

Distribution: Coastal San Diego County, western Riverside County; Baja California, Mexico

Habitat: Creek beds, seasonally dry drainages, and floodplains are the preferred historical habitat; usually on the periphery of willow woodland without a protective tree canopy. Riverwash and sandy alluvium underlie these locales. Some anomalous populations of this small herbaceous perennial are found in urban National City.

Known Sites: This species grows alongside the sidewalk on 12th Street east of Highland in residential National City. A robust colony on an embankment at the Lincoln Acres School is being carefully managed by school groundskeepers. A substantial population is reported near Hollins Lake. This site and areas immediately upstream and downstream become the only "natural" habitat where this species is still found in any significant numbers. Many reports from the Otay Valley area have proven to be the superficially similar Ambrosia confertiflora; some of these, likely misidentified, are carried in the CNDDB Data Base. Reports from below (i.e., west) of the Sweetwater Dam, as well as near Black Mountain Road at Peñasquitos Creek cannot be confirmed. Seed from the Hollins Lake site should be introduced at similar habitats in the region where other species of Ambrosia are not aggressively established. Most of the remaining populations within San Diego County are situated near Santee from Old Padre Dam eastward along the San Diego River. One site near Bonsall Bridge on the south side of the San Luis Rey River was recently graded. Historical reports near Lake Hodges cannot be confirmed extant. Other historical collections are from Spring Valley, 1.5 miles northwest of Sweetwater Dam, at Mission Valley 1 mile west of the San Diego Mission, and at San Luis Rey 0.75 mile west of the San Luis Rey Mission; most, if not all of these locales, are likely no longer extant. A biological survey report notes a site across the street from the Old Padre Dam parking lot. Data Base reports from San Diego County are for just south of Cajon Speedway in El Cajon east of Joe Crosson Drive and south of Denny Way, just southeast of the junction of Mission Gorge Road and Fanita Drive in Santee, the Gillespie Field Redevelopment Area in El Cajon east of Cuyamaca Street and north of Billy Mitchell Drive, and southeast of El Cajon near Cottonwood Golf Course at the junction of Steele Canyon Road and Jamul Drive. A possible small population of San Diego Ambrosia is found on unimproved Nichols Road northeast of Lake Elsinore in western Riverside County, approximately 0.5 mile west of the freeway in disturbed grasslands. No fruiting involucres could be located on the juvenile plants to positively confirm this sighting. A recent Data Base report is from Skunk Hollow in the Lake Skinner region. A small population grows next to a vernal pool near Nichols Road approximately 400 yards west of Interstate 15 and north of Lake Elsinore in Riverside County.

Collected by Reeder and Reeder (SD 109597) south in Baja California to Laguna Seca, 23 km south of Parador Catavina, where a pure stand covers much of the dried lake bed. Only six specimens are deposited at the San Diego Natural History Museum's herbarium.

Status: San Diego Ambrosia ia approaching extirpation in the United States. This species is recommended for listing as Federally Endangered. All existing sites should be protected. While many species of related "ragweeds" are quite invasive, the San Diego Ambrosia has good site tenacity but apparently does not readily colonize appropriate habitat. Field studies are needed to determine methods to propagate and successfully plant this species.

California Androsace [Androsace elongata L. ssp. acuta (Greene] Robbins

Listing CNPS List 4 R-E-D Code 1-2-2

State/Federal. Status -- None PRIMULACEAE Mar.-Jun.

Global Rank G?T3? State Rank S3.2?

Distribution: San Diego County, Los Angeles County, San Bernardino County, Kern County, Fremont County, Alameda County, Contra Costa County, San Joaquin County, Siskiyou County, San Luis Obispo County; Oregon; Baja California

Habitat: This minute annual is reported in openings in chaparral, coastal scrub, and cismontane woodlands. In the Cuyamaca Mountains it was observed in broad, grassy openings of a montane meadow.

Known Sites: A limited colony was seen on East Mesa in the Cuyamaca Mountains. An historical report is from Warner Hot Springs and an herbarium specimen was seen from Montezuma Valley. Hoover reports this species from San Luis Obispo County in grasslands from Cottonwood Pass to the Temblor Range and Carrizo Plain. Thomas reports this species form the Santa Cruz Mountains on serpentine in the Santa Clara Valley, near Stanford, four miles south of San Jose, and at Edenvale. Twisselmann reports California Androsace from Kern County as rare in small dense colonies in grasslands and Douglas oak woodland. Bowerman reports this species in the Mount Diablo region on grassy flats or open woodlands from locales in Alamo Canyon, a ridge east of Donner Canyon, and a ridge west of the Pioneer Road junction (including both white and pink flowered forms)

One specimen from Baja California was found at the herbarium of the San Diego Natural History Museum. It was collected at 32 27 1/2' North south southeast of El Condor by Moran (SD 110736).

Status: This inconspicuous species is likely undercollected; however, given the limited number of collections and known sites, California Androsace is presumed to be stable, but quite uncommon in the mountains of Southern California. All known sites in the Southern California region should be protected.

Copyright © May 1994 Craig H. Reiser.

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