Listen to the Desert Tortoise

Photo by: B. Eisenstein (4/17/2104)

The truck was parked on the side of a dirt road at the base of a slope in the middle of nowhere. Four of us - two botanists and two horticulturists - were walking back to the truck, eyes fixed on ground looking for some new flower we had missed on our way out. Just then I saw her. She looked like another dark gray rock, but right away I knew what it was. The desert tortoise was thoroughly unimpressed as the four of us gathered nearby - not too close - to admire her. A piece of vegetation dangled from her mouth as she took us in. Cameras snapped at the nonchalant, seemingly ageless sage (in the zoological sense). 

This was but one high point to a full day of desert exploration. Yesterday I was fortunate to be included in one of several teams of Rancho Santa Ana Botanic Garden scientists, educators, and horticulturists who scour the surrounding wildlands in search of wildflowers for the annual Spring Wildflower Show. The Wildflower Show brings some of the discoveries made by researchers to the public. As noted on the Rancho website:

Loeseliastrum matthewsii
(Desert Calico)
Photo by: B. Eisenstein

A tradition since the early 1930s, the Wildflower Festival is Rancho Santa Ana Botanic Garden's longest-running seasonal event and coincides with our state-recognized California Native Plant Week, (the third week of April each year). 

Over the years, the show has offered an opportunity for visitors to view flowers of species that they may not have otherwise been able to see. Flowers are gently prepared, carefully identified and exhibited indoors.

The week proceeding the show, teams of RSABG staff, volunteers and research associates undertake spring collecting trips to sites where studies to document the flora are underway, adding to scientific knowledge of these poorly known places and sharing the beauty of California wildflowers with Rancho Santa Ana Botanic Garden visitors. The geographically-diverse approach offers a diverse variety of species gathered and creates a beautiful and educational display.

In true Rancho style, this event brings together scientists, environmentalists, and all of those who appreciate the beauty and significance of Nature, so we can share our knowledge and wisdom, most of which we gain from stopping to watch the tortoise.

Desert tortoise in collection site. Photo by: B. Eisenstein

Upcoming field expedition for triple ribbed milkvetch

Astragalus tricarinatus on a cliff face near Mission Creek 

This coming spring the Conservation Program has an exciting new project that will be undertaken in some remote and underexplored sections of our California deserts to look for a federally endangered plant called Astragalus tricarinatus, or triple ribbed milkvetch as its known by its common name. This plant grows on an unusual geological substrate called “distressed granite” that is formed along the San Andreas Fault line where it bends and twists from its north/south trending direction to a more east to west trending direction in the Coachella Valley area. This Astragalus is a California endemic which means it is found nowhere else and is also considered a narrow endemic as its found in a relatively small area.

"distressed granite" outcroppings along the Pacific Coast Trail

The Conservation program had the great opportunity in the spring of 2011 to do surveys for Astragalus tricarinatus in the Whitewater and Mission Creek area where we visited many historic locations, found new undocumented populations, and collected a great deal of habitat information for this unusual plant, however a number of questions where left unanswered concerning some very old collections and literary references to this species being in other areas much more to the east. One of these curios historic records was left by a plant taxonomist named R. C. Barneby who was the leading expert on this genus in the 20th century. In his notes on Astragalus tricarinatus he wrote that it occurs in the Orocopia Mountains in Riverside County. While the Orocopia Mountains are geologically quite diverse, and in the path of the San Andreas Fault, they are still around 40 miles further east than the general area where Astragalus tricarinatus is found. There was no physical specimen of A. tricarinatus that we could locate from this range so all we have is Barnaby’s word that it grows there. While Barneby’s expert knowledge holds a lot of weight it is also important to have a physical specimen in a herbarium that can be visited and studied and this is one of the main goals for this project we will be undertaking, to locate A. tricarinatus in the Orocopias, asses population status and population numbers and collect as much information on this endangered plant that we possibly can.

Spencer's voucher from Chuckwalla Mtns (Harvard image)

One herbarium specimen we do have to go on, that has also been one of question, is a collection from 1921 from Mary Spencer that was apparently collected even further east in the Chuckwalla Mountains. The Chuckwalla Mountains are pretty far from the San Andreas Fault, and while they are made up of granite they don’t appear to have the “distressed granite” that Astragalus tricarinatus prefers. So this specimen brings up many more questions: can A . tricarinatus grow on other geological substrates besides “distressed granite”? There has been a good deal of visitation by botanists to this range in the past 100 years, so is it possible that at one time A. tricarinatus did occur here but no longer does? Was this perhaps a “waif” population? And while Mary Spencer wrote on her collection label “Chuckwalla Mountains” could she have been referring to a larger area that would also include the Orocopia Mountains? The only thing we know for sure right now is that the plant collected by Mary Spencer is definitely A. tricarinatus, we have this very important herbarium record that we can visit and reference, but the big question is: where exactly did she collect it? Perhaps she found the same population that R. C. Barnaby writes of. These are all questions we are hoping to answer this coming spring.