Fraga, Naomi .
Investigation of edaphic endemism in Erigeron parishii A. Gray (Asteraceae).
Erigeron parsihii A. Gray (Asteraceae), Parish’s Daisy, is a perennial herb that grows primarily on soils derived from carbonate deposits (limestone and dolomite) in San Bernardino County, California and is listed as threatened by the U.S, Fish and Wildlife Service. This species has a restricted natural distribution, with a range only 64 km long. Most populations occur on the northern slope of the San Bernardino Mountains where outcrops of carbonate substrate run on an east-west axis. Three occurrences are disjunct from the San Bernardino Mountains; two of these are located in Pioneertown 12 km to the SE, and one is 20 km farther south in Joshua Tree National Park (JTNP). The location of E. parishii in JTNP was essentially lost to California botanists and land managers for more than 60 years prior to 2005. Two herbarium vouchers from 1939 (RSA-POM) document E. parishii within JTNP. E.C. Jaeger collected these specimens, however Jaeger was known to intentionally obscure collection sites to preserve his favorite camping locations. Despite several reports of E. parishii at JTNP, the presence of E. parishii in the park has been questioned due to Jaeger’s ambiguous data and the fact that carbonate rock is not known to occur within JTNP. In 2005 populations were “rediscovered” in JTNP. Currently a total of 39 individuals is known to occur within JTNP. These plants appear to occur on granite. Additionally, in conducting surveys and examining herbarium material there appear to be morphological differences correlated with substrate preferences. A morphometric study is being conducted to evaluate these differences.
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Rancho Santa Ana Botanic Garden
1 - Rancho Santa Ana Botanic Garden, 1500 North College Avenue, Claremont, California, 91711, USA
Joshua Tree National Park
Presentation Type: Array
Location: PDR 4/Hilton
Date: Monday, July 9th, 2007
Time: 8:15 AM