Friday, December 2, 2016

A Pioneering Geologist on Uinta Plants


Required reading for my recent trip to the Uinta Mountains included several reports from early exploratory expeditions. The Uintas are rich in this kind of literature—the great pioneering geologists Ferdinand Vandeveer Hayden, Frank Emmons (working for Clarence King), and John Wesley Powell all passed through in the decade after the American Civil War. Their writing is scientific and filled with detail. But it's not boring, infused as it is with the excitement of discovery. Passing through the same landscapes, camping by the same rivers, pondering the same outcrops, I feel some of that excitement myself.

Though these men were geologists, they didn’t ignore plants. Usually they had a botanist along, or at least someone capable of collecting and preparing specimens. Those specimens that survived the rigors of travel were sent to experts, who studied and identified them, perhaps describing much-coveted “novelties”—species new to science. A plant list was included in the final report. The leaders themselves recognized the more common plants, and they often described the vegetation of the areas they passed through, in addition to geology, wildlife, natural resources, and any people they encountered.

In September of 1870, Ferdinand Vandeveer Hayden led his US Geological and Geographical Survey of the Territories into Brown’s Hole—the broad valley of the Green River in the eastern Uinta Mountains (now Browns Park):
“There is but little timber along the immediate valley of Green River—only a few bitter cottonwoods and willows; but on the hills there is a thick growth of the low piñon and cedars. … in the valley, there is a universal growth of the sage, (Artemisia tridentata,) greasewood, (Sarcobatus vermicularis, ) and Linosyris.
When I visited Browns Park 146 years later, also in September, I found the vegetation much the same. There were occasional stands of bitter cottonwoods (today’s narrowleaf and lanceleaf) along the Green River, and pinyons and “cedars” (junipers) covered the hills. In the valley bottom, sagebrush and greasewood were extremely common. But Linosyris? I had never heard of this “universal growth” plant. Yet there was nothing common I didn’t recognize. Did geologist Hayden really know what he was talking about? Was Linosyris a misidentification?

A google search revealed that Linosyris grows in Asia, Europe and Great Britain. There are no species native to North America. But when I looked at images, I realized Hayden probably was correct … probably he was just another victim of nomenclatural change.

According to Google, the three plants below are called "linosyris." What very common plant of the basins of the American West do you think Hayden saw? [1. Type specimen of Linosyris (Aster) grimmii from Turkestan, Muséum National d'Histoire Naturelle; 2. Galleta linosyris (“goldilocks”); 3. Linosyris villosa, Russia, maybe today's Aster oleifolius.]

As botany students, we’re repeatedly assured that scientific (Latin) names avoid the horrendous ambiguity of common names. But then when we go out into the real world, we quickly learn that these names change too, as taxonomists study and reclassify plants. To make things worse, experts don’t always agree. Old literature is especially challenging.

But Hayden’s Linosyris puzzle was easy to solve. In the “Catalogue of Plants” at the end of the report was Linosyris graveolens, under Compositae (Aster family). graveolens and compositae were the final clues. This is our rubber rabbitbrush, Ericameria nauseosa var. graveolens, which used to be a member of the genus Linosyris.

Rabbitbrush is extremely common in Browns Park. It definitely qualifies as “universal growth”—especially in September when it’s covered in flowers.
Bright golden floral displays can’t be missed.
Rubber rabbitbrush in morning sun.
Stems have a felt-like covering of dense white hairs.
As you may have guessed, rabbits like rabbitbrush. In fact, many wildlife species benefit from its abundance. Birds and small mammals use it for cover. Deer, antelope, elk, small mammals and birds feed on the leaves, flowers and seeds. Rabbitbrush is visited by a wide range of native insects, especially in late summer and fall. It’s said to support more native bee pollinators than any other cold desert shrub in the Intermountain West (Waring 2011).

Typical of the Aster family, what look like rabbitbrush flowers aren’t flowers. They’re small heads of tiny flowers, each with reproductive parts—stamens and pistils. [The Aster family was originally called Compositae because what look like flowers are actually composites. Not that long ago, it was changed to Asteraceae to be consistent with naming rules.]
The pungent flowers explain the scientific name, Ericameria nauseosa. But they're not that bad. I would say resinous rather than nauseating.
Flowers are tubular, less than a half inch long. Stamens and pistils emerge from the tubes. Source.

I took many photos of rabbitbrush in Browns Park … unintentionally. It was that common.
With dark dikes intruded into the ancient Red Creek Quartzite (more here).
With more rocks from the core of the long-gone Red Creek mountain range.
On a CO2 pipeline project (more here).
Approaching the Gates of Lodore on the Green River.
Rabbitbrush lined most of the roads in Browns Park, which isn't surprising since it thrives on disturbed sites. It often dominates initially, but in the absence of continued disturbance, becomes just a minor part of the native vegetation.
Above and below: rubber rabbitbrush along the Irish Canyon road, which cuts through the north flank of the Uinta Mountains near the east end of Browns Park.
Rabbitbrush is taking over the dugout where James Jarvie lived in 1880, his first year in Brown’s Hole.

In between Linosyris graveolens and Ericameria nauseosa, rubber rabbitbrush was called Chrysothamnus nauseosa. This is my choice of names because Chrysothamnus means “golden shrub”—which they certainly are! Rabbitbrushes are super difficult to classify, and experts surely will continue to rename them. Maybe someday some taxonomist will move rubber rabbitbrush back into Chrysothamnus, proving me prescient ;-)

Rubber rabbitbrush is the most complex of the rabbitbrushes, with 24 subspecies and varieties, many of which overlap or hybridize. Within these, there are multiple ecotypes, for example adapted to different soils. And within ecotypes there’s a “great deal of variability in morphological characteristics and chemical composition” (Scheinost and Ogle 2010). No wonder rubber rabbitbrush is so successful—so widespread and common. And no wonder rabbitbrush taxonomists struggle to classify them. In this case, maybe it’s best to use common names after all.
Rubber rabbitbrush and rainbow on my last day in Browns Park.


Anderson, L. 1995. The Chrysothamnus-Ericameria connection (Asteraceae). The Great Basin Naturalist, 55:84-88. Retrieved from

Porter, TC. 1871. Catalog of plants. in Hayden, FV. Preliminary report of the United State Geological Survey of Wyoming, and portions of contiguous territories. Washington: Government Printing Office. [Thomas C. Porter was professor of botany, geology and zoology at Lafayette College in Easton, Pennsylvania.]

Scheinost, PL, Scianna, J, and Ogle, DG. 2010. Plant guide for rubber rabbitbrush (Ericameria nauseosa). USDA-Natural Resources Conservation Service, Pullman Plant Materials Center, Pullman, WA. Accessed 2016, November 29.

Tirmenstein, D. 1999. Ericameria nauseosa. In: Fire Effects Information System [Online]. USDA Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory. Nomenclature updated 2014. Accessed 2016, November 29.

Waring, GL. 2011. A natural history of the Intermountain West; its ecological and evolutionary story. University of Utah Press.


  1. Ooh, just gorgeous photos of a gorgeous area. You're so right about botanists changing names--I get that with more research and observation, that makes sense, but it's hard on those of us with not much background! :) I do tend to love the common names because of their charm and poetry, but it's good to at least be familiar with what family a plant is in. Are the rabbitbush plants you profile somewhat resistant to natural (or otherwise, I guess) fires?

    Great post!

    1. Thanks, Tina. From all I've read, rabbitbrush *loves* fire! It can sprout from the root crown or any surviving stems, and apparently lots of seeds blow in. It's said to often be one of the first plants to colonize burns within its habitat range (or one of the first perennials? ... hard to believe it can out-compete some of those annuals, but maybe ...)

  2. Curiously, although I too prefer the name Chrysothamnus, it was enlightening to grow another Ericameria, E. laricifolia, alongside the rabbitbrush. While the former has a strong - and often cited - resemblance to Damianita (Chrysactinia mexicana), the seedheads* are nearly identical (to my untrained eye, at least) to those of Rubber Rabbitbrush.
    It's a wonderful plant here in the low desert too, and I can vouch for its popularity with the bees! Thanks for explaining the origin of the "nauseosus" part of the name, which I could never understand. I had been worried it would make my horse ill if he decided to eat it...!
    Your final photo with the rainbow is beautiful... :)
    *What is the correct term?

    1. Amy, from everything I've read, the foliage is not toxic. Wildlife will browse it heavily in winter, I suppose when there's nothing more tasty around. As for correct term, I'm not sure! I call the clusters of tiny flowers "heads" -- the technical term is capitula (pl.) But do I really want to say "dandelion head"?! When in fruit they become "seed heads" The entire cluster of heads is the inflorescence ... maybe i've answered your question ;-)