Southern Tarplant [Hemizonia parryi (Greene) ssp. australis Keck]

Southern Tarplant [Hemizonia parryi (Greene) ssp. australis Keck]

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

State/Federal. Status -- None ASTERACEAE Jun.-Nov.

Global Rank G5T2 State Rank S2.1

Distribution: San Diego County, Orange County, Ventura County, Los Angeles County, and Santa Barbara County

Habitat: Valley and foothill grasslands, alkaline locales, and peripheral Salt Marsh are all utilized by the Southern Tarplant. At the Del Mar locale the soils are mapped as Chino silt loam and the salt marsh vegetation is found only yards away. At Newport Back Bay this tarplant grows in mesic grasslands with an ocean influence; most of the surrounding vegetation here consists of invasive non-native weeds.

Known Sites: A small colony is immediately east of Interstate 5 and south of Via de La Valle on the periphery of the Salt Marsh. Agricultural fields are extending into the Salt Marsh to the south of this site. It is reported around the large vernal pool near the Ramona Airport and reported from several locales in this area in similar habitat including west of Rangeland Road. Much of this species' probable habitat no longer exists; it is largely farmed or developed. A number of scattered colonies occur at Newport's Back Bay in Orange County centered near the bike bridge which crosses Delhi Channel; one site was seen across the bay along the shoulder of Back Bay Drive. Other reports in Orange County are from Bonita Canyon on the Irvine Campus, near the Peters Canyon Channel by the intersection of Walnut Avenue and Harvard Avenue east of the Tustin Marine Helicopter Station, at the mouth of the Santa Ana River, Near Kalmus in Costa Mesa, and along a graded slope at the Wintersburg Flood Control Channel near Bolsa Chica. Also to the north of San Diego County are reports where possibly no longer extant from the Bryant Ranch in Long Beach, below Long Beach State near Pacific Coast Highway, in low bottom ground on the San Gabriel River in Long Beach, east of Isla Vista School in Goleta at Santa Barbara County, on Santa Catalina Island in an open field above a golf course, and in Del Ray in Los Angeles County at Lower Ballona Creek. Historical locations in Orange County noted by Roberts at Santa Ana, Rossmoor, Cypress, Westminster, and Garden Grove are all possibly extirpated. Reported by Smith for the Santa Barbara area between Goleta and Ellwood in sandy fields near the ocean, and along the railroad tracks near Pitas Point.

Four locales have herbarium specimens for Baja California at the San Diego Natural History Museum; south to 30 29' North where collected by Moran (SD 68050) 3 miles east of San Quentin in a vernal pool. Two other Baja locations are at Las Juntas, Ejido Papalote, and 1.4 miles southwest of Redondo Station. An additional Baja station where reported is 17.5 miles east of Tijuana on the road to Tecate.

Status: The Southern Tarplant is almost extirpated in San Diego County and severely declining throughout its U.S. range. The few remaining San Diego County sites are threatened by development; extensive recreational use of Newport Back Bay in Orange County threatens various scattered colonies. This should be a candidate species for Federal Endangered status; all sites should be protected.


Copyright May 1994 Craig H. Reiser.

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