Last August, on one of my first days of field work on Tejon Ranch, I spent some time collecting plants on a virtually-unexplored carbonate rock outcropping on Blue Ridge with Neal Kramer. Neal had recently found a large population of the Tejon endemic buckwheat, Eriogonum callistum, at this location and we were eager to uncover what other gems might occur at this location. That day we made collections and observations of a Lomatium in very late phenology-only in fruit and almost completely dormant.
The genus Lomatium, also known as biscuit roots, is a large group of plants in the carrot family (Apiaceae) restricted to North America, and containing approximately 75 described species. In California, there are 47 taxa (this term includes species, varieties and subspecies), 21 of which are listed as rare by the California Native Plant Society.
Based on those few drying plants, Neal and I thought the plants might be close to either L. utriculatum or L. mohavense, but the characters just didn’t seem to fit either of these species. At that point in time, we made note to return to this population the following year to collect better specimens that include all of the characters needed for identification.
This field season I made observations and collections of the Blue Ridge Lomatium at a number of locations, making sure to obtain samples of the plants in flower, and in fruit. These specimens were resting contently in my herbarium cabinet when Jeff Greenhouse, a research associate at the Jepson Herbarium, sent me an email a couple of weeks ago asking if I’d had the chance work on the Lomatim Neal had collected on Tejon Ranch. He indicated that he and Neal had spent some time looking the specimen Neal had collected last year and were having a hard time placing a name on it. That same day I spent several hours looking at my specimens, comparing them with Lomatium specimens housed in the RSABG herbarium. Much like the Jeff and Neal’s experience, I was puzzled by attempts to identify my specimens of the Blue Ridge Lomatium.
Fast forward a couple of weeks, I have now spent hours looking at Lomatium specimens, shown my plants to numerous researchers here at RSABG, and sought help and advice from my advisor, Dr. J. Mark Porter. Mark suggested that we start to solve this problem by doing some comparisons of morphological characters of the Tejon plants with similar species. I think it is now safe to say that I have gotten Mark hooked into helping me to solve the Tejon Lomatium puzzle. Mark has now spent countless hours rehydrating leaves, inflorescences, and fruits from many Lomatium specimens and taking photos with a camera attached to a dissecting microscope. This detailed work is necessary to compare the traits of the Blue Ridge Lomatium with other species.
Based on this research we are becoming more convinced each day that the Blue Ridge Lomatium is an undescribed species. It is now clear that the Tejon plants are probably closely related to L. macrocarpum, a species that reaches the southern end of its distribution in the southern Sierra Nevada.
At this point in time, however, there are a number of characteristics that lead us to think that these plants are quite different from L. macrocarpum. Below is a table comparing preliminary data from measurements of the Blue Ridge Lomatium with L. macrocarpum:
|L. macrocarpum||Blue Ridge Lomatium|
|Involucel (the bracts below each flower cluster) shape||very reduced on 1 side to absent on 1 side||not reduced on one side or only slightly so|
|Involucels reflexed in fruit||yes||no|
|Fruit length||9-20 mm||6.9-9.7 mm|
|Flower color||white, cream, purple||bright yellow|
|Leaflet shape||linear to oblong||ovate to lanceolate|
As you can see there are many characters that easily differentiate these two plants. We are also currently analyzing additional morphological characters that may prove to be informative in distinguishing the Blue Ridge Lomatium from other taxa. Further research will involve comparing one or more gene regions from this putative new species with other Lomatium species to determine its phylogenetic placement (essentially where it is located in the Lomatium family tree). This information will help us to determine if the Blue Ridge Lomatium should be published as a new species or a new variety of L. macrocarpum.
As I prepare for my next collecting trip (yes, there are still plants to collect even in September of this very dry year!) I am elated and filled with anticipation, because in under-explored regions like Tejon Ranch you truly never know what you are going to find. This Lomatium and the other potentially new species, including a Streptanthus and Heterotheca, that I continue to conduct research on are evidence of this. For me, being involved in the process of scientific discovery is one of the things that make me passionate about conducting botanical research.
Remember my earlier post on Eriogonum callistum? Well, here is one of the plants we grew in the nursery at RSABG, flowering in its first growing season. What a beautiful plant!