Eschscholzia californica

Eschscholzia californica (California poppy) represents a highly variable complex; over 90 taxa have been described (Hickman 1993). Currently, two subspecies are recognized by many authors, including Hickman (1993) and Kartesz (1999): subsp. californica (native in the western U.S. and northern Mexico, and apparently the one used in gardens and cultivation and now spread throughout much of the continental United States) and subsp. mexicana (restricted to California, Arizona, Nevada, Utah, New Mexico, and Texas) (Kartesz 1999, USDA-NRCS 1999, Welsh et al. 1993, Gleason and Cronquist 1963, Nelson and Williams 1992). One segregate species, E. procera, was considered for U.S. federal listing but received '3C' status (not meriting listing because adequately protected or too common); it is not recognized in recent major floristic works.

This species is native in a moderately large range in the western U.S. states and northwestern Mexico (and is now widely cultivated, and frequently established and persisting outside cultivation in much of the rest of the U.S. and southern Canada). In its native range, the plant is threatened by habitat alterations and genetic contamination of wild populations with genes from cultivars from roadside wildflower plantings.

E. californica presently occurs from western Canada through Texas and in all states in between. Eastwards, it is found in a few plains states and in most states east of the Mississippi River (USDA-NRCS 1999).

Apparently, the native range of this species is the southwest U.S., as far east as Utah; occurrences further east are apparently escapes from cultivation, or resulting from "wildflower," roadside, or reclamation plantings (Nelson and Williams 1992, Welsh et al. 1993, Weber and Wittmann 1996a, Gleason and Cronquist 1963).

Subspecies mexicana is apparently native to west Texas (Correll and Johnston 1970), westcentral and southwestern New Mexico (Martin and Hutchins 1980), all but the northeastern portion of Arizona (Kearney and Peebles 1960), northern Sonora (Kearney and Peebles 1960), extreme southwest Utah (Albee et al. 1988), along the Colorado River corridor into far southern Nevada (Nevada Natural Heritage Program, Kartesz 1988), and desert mountains of California (Hickman 1993). Kartesz (1999) considers it extant in all these states.

Hickman (1993) lists the range of subspecies californica as California to southern Washington, Nevada [western], New Mexico, and northwest Baja California, although the western Nevada occurrences may have spread from plantings (Nevada Natural Heritage Program). It has apparently spread from cultivation throughout much of the eastern and western United States and Canada (Kartesz 1999). It is reportedly introduced and non-native to Illinois, Michigan, British Columbia, Manitoba, Wyoming, Ontario, Tennessee, and Missouri (Natural Heritage Programs).

An attempted introduction of this species was purportedly made in the Franklin Mountains near El Paso, Texas, but the plant failed to persist at this location (Bill Carr pers. comm.).

With the rampant use of E. californica for landscaping purposes and roadside wildflower plantings, the primary threat to this species appears to be the genetic contamination of wild populations. This, coupled with the encroachment of human activities on the historic native habitat of this species is resulting in a large scale, human induced transformation in the distribution and genetic composition of this species.

Although subsp. californica appears to be the primary taxon used for landscaping and roadside plantings, in Arizona, subspecies mexicana is also seeded along the roads and sold in desert nurseries (Sue Schuetze pers. comm.).

Throughout most of its current range, harvest of this species for the medicinal plant trade does not pose a significant threat, since it has been so widely introduced. However, some remaining small, high quality natural populations could conceivably be threatened by this practice in parts of the original range of this species. There are currently no reports that individual populations have been negatively impacted or extirpated due to collection for the plant trade.

An individual familiar with U.S. trade in herbal medicinals estimates that trade in this plant for medicinal purposes is on the order of 250 pounds per year (McGuffin pers. comm.). The aboveground parts are used.