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Friday, May 23, 2014

Tejon Ranch Botany- by Dr. Bruce Baldwin, Curator of the Jepson Herbarium, UC Berkeley

To a Californian botanist, Tejon Ranch has a strong allure as an ecologically intact, biogeographic crossroads that until recently has been under-explored for native plant diversity.  That attraction is heightened by the ecological transitions that occur within the Ranch and the potential for evolution across such a varied landscape.  From those perspectives, Tejon Ranch is ideally situated to study and preserve plant diversity and the processes that give rise to it.  The Ranch spans major floristic units and climatic regions, with the Mediterranean-like climate of the California Floristic Province (CA-FP) to the west and Mojave Desert to the east, and much local variation in climatic and soil conditions associated with finer-scale topographic, elevational, and geological diversity.  These considerations make the Tejon Ranch one of the most important areas for plant conservation in our rapidly changing state.

Steve's pincushin (Chaenactis stevioides), photo courtesy of Bruce Baldwin
Evolutionary transitions between desert and Mediterranean-like conditions, and between low-elevation and high-elevation settings, have been important in a wide diversity of Californian plant groups and are of interest in our ongoing studies of plant diversification at the Jepson Herbarium (UC Berkeley).  In the sunflower family (composites), some major lineages that are endemic to western North America are excellent subjects for examining such shifts.  A particularly notable example is well represented at Tejon Ranch: the pincushion genus, Chaenactis.  We are currently revisiting Kyhos’s (1965) classic investigation of the origins of desert annual pincushions from CA-FP ancestors by comparing DNA sequences and examining other fine-scale differences between populations, with extensive sampling across the distributions of these plants.  Recent sampling at the Tejon Ranch filled a critical geographic gap in our coverage of the CA-FP/desert border and spanned four key species for understanding CA-FP/desert transitions within Chaenactis (C. fremontii, C. glabriuscula, C. stevioides, and C. xantiana).  Significant late-season precipitation made collecting on the eastern slopes of the range much more successful than expected.  

Pringle's wooly sunflower (Eriophyllum pringlei), photo courtesy of Bruce Baldwin
Another plant group of interest for examining major ecological shifts is the woolly sunflower group, Eriophyllum (woolly sunflower), Pseudobahia (sunburst flowers), and Syntrichopappus (Fremont’s gold).  We were fortunate to sample both species of Syntrichopappus on the same trip, which was quite a coup considering the miniscule size and lack of previous collections of S. lemmonii on the Ranch.  Ecological transitions in both woolly sunflowers and pincushions have included shifts in life history from annual to perennial, in the opposite direction once “allowed” by some plant anatomists, but as now resolved for a number of other Californian plant groups that have migrated into montane or coastal regions.
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While collecting, we were able to enjoy the spectacular spring bloom on the desert side of the Ranch, including a surprisingly floriferous wetland with the rare Palmer’s mariposa lily in full bloom, unusual plant associations in the Mediterranean-desert transition, and a remarkably stout form of valley oak.  
Yellowray Fremont's gold (Syntrichopappus fremontii), photo courtesy of Bruce Baldwin

 Many thanks to Mike White and Nick Jensen for ensuring the success of our visit and for sharing their knowledge of the ranch and its magnificent flora.  The Tejon Ranch Conservancy should be commended for their efforts to promote study and preservation of the botanical values at Tejon Ranch.

Palmer's mariposa lily (Calochortus palmeri) blooming in 2013
Dr. Baldwin is the Curator of the Jepson Herbarium and a Professor in the Department of Integrative Biology at UC Berkeley. A native of central coastal California, he attended Arroyo Grande High School in Arroyo Grande, California. He first became interested in plant diversity through backpacking and exploring in the floristically-rich Santa Lucia and San Rafael Mountains of central western California. He received his B.A. degree in Biological Sciences from U. C. Santa Barbara in 1981. He received his M.S. (1985) and Ph.D. (1989) degrees in Botany from U. C. Davis (with Donald Kyhos) and conducted postdoctoral work at the University of Arizona, Tucson (with Michael Donoghue and Robert Robichaux). He was a member of the Botany faculty at Duke University for two years before moving to Berkeley in 1994.