BRODIAEA SANT AROSAE (THEMIDACEAE), A NEW RARE SPECIES FROM THE SANTA ROSA BASALT AREA OF THE SANTA ANA MOUNTAINS OF SOUTHERN CALIFORNIA

摘要

Brodiaea santarosae (Themidaceae) is a new species from southwest Riverside County and immediately-adjacent Miller Mountain of San Diego County, CA. It is easily distinguished from other Brodiaea species in southern California by its large flowers anddistinctive, variable staminodes; morphological analysis revealed 11 total differentiating characteristics. Brodiaea santarosae occurs only on or very close to the 8-11 million-year-old Santa Rosa Basalt. It has the smallest range of the southern California Brodiaeas, with just four known populations occupying only a small portion of a -40 km~2 area, plus a fifth small population disjunct by 11 km. It has been speculated that the B. santarosae population is a hybrid swarm between B. filifolia and B. orcuttii, based solely on the appearance of the staminodes and filaments in selected flowers. This speculation was rejected due to the lack of sympatry between the three taxa and because specimens of B. santarosae have numerous characteristics that are notintermediate between the claimed parent taxa. In contrast, intermediate characteristics were seen in Fl specimens of B. filifolia X B. orcuttii discovered in San Marcos, CA, the only location where those species overlap. We also report extensions to thelength characteristics for both B. filifolia and B. orcuttii and demonstrate that two populations of B. filifolia previously thought to be hybrids are consistent with other B. filifolia populations.