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Thursday, January 21, 2016

A New Plant List for Tejon Ranch! By Dr. Mike White, Conservation Science Director

I am happy to announce that we are converting to a new plant list!  Why should you care you ask? The lists that we keep for Tejon Ranch are records of all of the taxa that occur here. [Note: Taxon (plural - taxa) means species, subspecies or varieties of plants and animals. Technically we refer to the two subspecies of a single species (e.g., Eschscholzia lemmonii subsp. kernensis and Eschscholzia lemmonii subsp. lemmonii) as two taxa.] It is one way of documenting the biodiversity of the Ranch, which the Conservancy is charged with protecting, enhancing, and restoring. It also allows us to more fully understand the ecology of Tejon, so to better plan and execute our conservation management activities.
Tejon poppy (Eschscholzia lemmonii subsp. kernensis)

The plant list that we have been using at the Conservancy originally was based on species lists that were generated by consultant surveys of Tejon Ranch Company’s future development areas, and then augmented over the years by the Conservancy’s partners and citizen scientists.  However, plant taxonomy is often based on subtle distinctions in physical characteristics that can be difficult to discern, and is ever-changing based on new research. Without a physical specimen (voucher specimen) for reference, plant identifications can be uncertain and open to disagreements. Having physical specimens of a plant allows plant taxonomists to revisit specimens and the taxonomic names that were assigned them, confirm their identifications if there are questions, and revise their taxonomy in the future as appropriate. If available, a voucher-based species list is a more accurate and powerful tool than one based on unconfirmed identifications, and vouchering specimens is a standard practice of research botanists around the world.
Syntrichopappus lemmonii

The Conservancy is fortunate to have Nick Jensen of the Rancho Santa Ana Botanic Garden working on the Flora of Tejon Ranch for his graduate research ( and access to his extensive voucher-based plant list.
Nick Jensen with Brickellia nevinii
Given Nick’s significant research efforts at Tejon, the Conservancy has decided to abandon our old plant species list in favor of a new voucher-based list derived from Nick’s work to date. The list is a work in progress for Nick as well as the Conservancy, and we will provide updates as appropriate.

A few of the highlights from the new list:

  • There are 968 plant taxa on the list. For context, there are 8,500 plant taxa in California, so Tejon Ranch supports over 10% of the state’s plants in less than 1% of its area.
  • Of the 968 taxa, about 88% are native to California (that’s good!).
  • Those 968 plants occur within 103 different plant families, representing nearly 60% of the plant families present in California.
  • The Sunflower family (Asteraceae) had the highest number of plant taxa at 149.  The next highest was the Grass family (Poaceae) with 73 taxa.
  • There are 12 oak taxa (genus Quercus) at Tejon, representing about 1/3 of the oaks in the state.
  • Some plant genera are particularly rich at Tejon Ranch.  These include the genera Eriogonum (buckwheat) with 27 taxa; Gilia with 18 taxa; Lupinus (lupine) with 15 taxa; and Clarkia (farewell-to-spring), Cryptantha, Mimulus (monkey flower), and Phacelia each with 13 taxa.
  • Nick has documented 42 California Native Plant Society (CNPS)-designated rare plants, a 50% increase in the rare plants known to occur on the Ranch prior to his work!
  • Perhaps most interesting, Nick has found at least three plants that may represent new species to science!

A Lomatium from the Blue Ridge that Nick believes is new to science.