Botanical Perplexity in the Southern Utah Desert

The bush on the left isn’t dead.

On the Waterfall Trail behind the San Rafael Reef, west of Arches National Park, I came across an unfamiliar shrub. From a distance it looked dead, but up close I saw small green oval leaves with serrated upper margins, and fruit that looked like tiny immature apples. These suggested serviceberry, the genus Amelanchier, and I felt that pleasing cognitive dissonance that comes when something is both familiar and strange. I looked forward to solving the mystery, putting a name on this shrub.

The small glabrous (not hairy) leaves were problematic.

Developing fruit, with anthers and styles still visible.

Serrated leaves and pomes of Amelanchier (Juneberry, Serviceberry); source.

This was supposed to be a short post—put together quickly, just a few photos and some information about the serviceberry, finishing with a sunset. But identification proved elusive, in part due to the small glabrous (hairless) leaves that didn't fit any Utah species, but mainly because of the legacy of struggling Amelanchier taxonomists.

The overlapping and highly variable “species” of this genus confound even the experts. In 1946, eminent botanist Merritt Lyndon Fernald went so far as to claim that no other genus in North America, except perhaps Rubus and Crataegus (raspberries and hawthornes), offered as much “perplexity” as Amelanchier (1).

The serviceberry I saw along the Waterfall Trail is a case in point. For a century botanists have debated its status, moving it from species to subspecies to synonym and most recently back to species. Not surprisingly, my path through the literature was tortuous. But I did meet some interesting characters, starting with Ivar Frederick Tidestrom.

I.F. Tidestrom, photo courtesy USGS.

Ivar Tidestrom ran away from home in Sweden in 1880, and headed for the United States. He served in the US Army (cavalry), enrolled in the University of California as an engineering student, and soon switched to botany. In 1919 while collecting plants in the Charleston Mountains northwest of Las Vegas, Nevada, he found an unfamiliar serviceberry with small glabrous leaves in the “piñon belt near Wilson’s ranch”. Four years later, he published it as a new species: Amelanchier nitens.

Amelanchier nitens, collected by Ivar Tidestrom on May 27, 1919; US National Herbarium.

In the late 1930s, Ira Waddell Clokey, a mining engineer and botanist, was finishing up his intensive study of plants of the same Charleston Mountains. He went to Tidestrom’s site to collect more material of Amelanchier nitens. He concluded it didn’t warrant full species status. Instead, he called it Amelanchier utahensis ssp. covillei (Clokey 1945).

Ira Clokey died in 1950, just after his Flora of the Charleston Mountains was accepted for publication (source).

Around the same time, G. Neville Jones took on a revision of North American Amelanchier, published in 1946. He described Tidestrom’s serviceberry from the Charleston Mountains as an “extreme form” that “intergraded completely with the typical pubescent [hairy] forms” of Amelanchier utahensis, a widespread and highly variable species (2). Thus Amelanchier nitens was reduced to synonymy, becoming part of Utah Serviceberry, where it remained for almost 60 years.

The latest revision of Amelanchier was done by Christopher Campbell and five colleagues, for the Flora of North America (2015 online). In it, I found a species description that matched the serviceberries along the Waterfall Trail pretty well—Amelanchier nitens! So we’ve come full circle. Tidestrom’s serviceberry has been resurrected as a species, now with a common name—Shining Shadbush (shining for the glabrous leaves; shadbush is one of many common names for Amelanchier).

Does Shining Shadbush grow in the “piñon belt” of Utah?

Did I finally have a name for my mystery shrub? Maybe. Unfortunately, Shining Shadbush is said to grow only in the Charleston Mountains in Nevada and in a limited area near Sedona, Arizona, i.e., not in Utah. But then I read the fine print (emphasis added):

“The authors have observed incomplete herbarium specimens conforming to Amelanchier nitens morphology from Colorado, New Mexico, and Utah.”

So the serviceberries along the Waterfall Trail may be the Shining Shadbush, Amelanchier nitens. But given the “perplexities” of serviceberry classification, it’s probably best not to worry about a name. Instead, just enjoy Amelanchier’s approach to biodiversity!

Thus ends my winding tale ... except for the sunset. Here’s one looking south from the Waterfall Trail.

West side of San Rafael Reef, Henry Mountains in distance.

Notes

(1) In the Introduction to his American Species of Amelanchier, G. Neville Jones (1946) summarized the evolving struggle of taxonomists to classify serviceberries, with wild swings in numbers of species (emphasis added):

“The earlier students [19th century] of the North American flora, including Michaux, Pursh, Nuttall, Torrey, and Gray, took the view that [Amelanchier] in the western hemisphere consisted of only one, or at the most very few, highly variable species. … there now may be found in botanical literature nearly two hundred binomials and trinomials representing the species of Amelanchier in America.”

(2) Jones also described convincingly the challenge of serviceberry identification:

“Anyone who studies Amelanchier in the field, or who examines large series of specimens in herbaria, is at once struck by the extraordinary variation of the foliage that occurs even in the same species, as manifested in different stages of development and from various habitats. … When placed side by side, specimens of the same species in these different stages of development often show an almost incredible dissimilarity and have been not infrequently mistaken for different species.”

Sources

Most of these were accessed online via the Biodiversity Heritage Library. Their wonderful collection is newly enhanced with Full Text Search, more information here.

Campbell, CS, et al. 2015 (online). Amelanchier, Flora of North America vol 9. http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=101333

Clokey, IW. 1945. Notes on the flora of the Charleston Mountains, Clark County, Nevada. Madroño 8:56-61. https://biodiversitylibrary.org/page/47877692

Clokey, IW. 1951. Flora of the Charleston Mountains, Clark County, Nevada. University of California Press (Amelanchier pp 119-120). https://books.google.com/books?id=GuBVI1nC-50C&source=gbs_navlinks_s

Jones, GN. 1946. American species of Amelanchier. Urbana: The University of Illinois Press (A. nitens pp 92-93). https://www.biodiversitylibrary.org/item/105913 

Tidestrom, IF. 1923. New or noteworthy species of plants from Utah and Nevada. Proceedings of the Biological Society of Washington 36:181-184. https://www.biodiversitylibrary.org/page/34510710#page/201/mode/1up

Tidestrom, IF. 1925. Flora of Utah and Nevada. Contributions from the United States National Museum 25 (Amelanchier nitens pp 282-284). https://catalog.hathitrust.org/Record/001494238

Back to the Misty Mountain

Is this the way?

This month’s gathering of tree-followers coincides with an unfortunate event in American history, culminating months (or was it years?) of depressing “discourse” on both sides. Is it time to leave? They say the Canadian immigration website crashed Tuesday evening, overwhelmed by US traffic. But I don’t want to leave, I like it here! I think I will go back to the Misty Mountain instead, if I can find the way.

The Misty Mountain is metaphorical—a composite of wild places and other patches of nature. I moved there forty years ago after paying off my student loan, but at some point I fell off, landing on the Human Highway. Is it possible to return? We’ll see.

The journey started at Hutton Lake, with a visit to the serviceberry I’ve been following since January. It grows in an unexpected forest along the south side of the lake, on the shady north side of a ridge of steeply-tilted sandstone.

A cool but sunny calm day (yes, calm!) in the Laramie Basin.

Dry brown November landscape, with greasewood and grass.

The prairie dogs are all hibernating, maybe dreaming of tasty green herbaceous plants.

I reached the ridge and hiked along the crest, then descended to lake level and strolled through the tiny forest.

Bare aspen, cottonwood and serviceberry trees, with tilted sandstone.

Lots of buds on the aspen trees ... they're ready for next year!

Fossilized ripples on a 100-million-year-old beach. It was uplifted and tilted when the Rocky Mountains rose.

Aspen sapling survives on rainwater that accumulates in cracks.

My serviceberry tree was bare of leaves and berries, looking pretty much as it did back in January when we met.

My tree and more ripples.

Lots of buds.

Then a large brown object swooped down from the sky and landed in a cottonwood tree nearby. Who hoo hoooo is this?!

Click on photo to view (center).

Did I wake her? I thought she preferred to fly at dusk.

It was an eared owl of some kind (“ears” are tufts of feathers), maybe a long-eared. Do you know? I think this is too slender an owl to be a Great Horned, but I’m no expert. [UPDATE: great horned owl after all.] She hung out while I photographed the serviceberry, changing her perch occasionally. When I left, she was still there, watching.

I headed back, past the tough little serviceberry on a pedestal (more here) ...

... and past castles rising from lakeshore muck. Are these homes of fairy creatures?

I wish! But no, just dead aspen saplings from years back, when the lake was lower. Now they're wrapped in salt-encrusted decaying aquatic plants. The lakeshore has a rich aroma this time of year.

Next I met a muskrat.

He was much more cautious than the owl and quickly dove, leaving a circle of ripples. I sat on the bank hoping he would return. Finally he did, staring at me just long enough for another photo before diving and swimming off again. I left so he could continue whatever business he had going there.

Cautious muskrat watching me (center of photo).

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I come down from the misty mountain

I got lost on the human highway

Take my head refreshing fountain

Take my eyes from what they've seen.

—Neil Young, 1978

Plant on a Pedestal

Awe-inspiring!

This month I’m making an oblique and tenuous segue from Tree-Following, for I have no news to report of my serviceberry. After a long vacation, all kinds of things have to be done right away! (of course ;-) Instead, this post is about one of its brethren growing nearby under challenging circumstances. Though it’s only a meter tall and technically a shrub, it’s as impressive and inspiring as a tree.

The serviceberry doesn’t sit directly on the ground but rather on a pedestal—which sounds lovely, but it was created by “erosion of soil from around the base of a plant such that it appears to be on a pedestal” (source). [Pedestaling usually refers to erosion, but frost heaving and accumulated soil or litter can create pedestals too. And I stumbled across a webpage that mentioned plants with pedestals of lateral roots—news to me.]

Plant on a pedestal created by erosion. Arrow points to exposed roots (source).

Range managers consider pedestaled plants indicators of over-grazing. A healthy allotment (pasture) has no pedestaling. If mature plants are on pedestals, the allotment is said to be at risk, and the stocking rate should be reduced. In worst cases, erosion has pedestaled all plants and exposed roots. These allotments are classified as unhealthy. Complete removal of livestock may be necessary for the range to recover.

The pedestal has all but disappeared, leaving the serviceberry standing on its roots.

But this serviceberry grows where no cow would ever think of going—on a steep slope where there's little to eat. However, slope and rock type make erosion inevitable. At the same time, the tilted beds of sandstone and siltstone offer benefits. Soil develops from softer siltstone. Seeds germinate, grow into seedlings, and send roots down to the water that falls as rain, and accumulates in underground fractures in the sandstone.

Serviceberry on Boulder Ridge (center of photo); Hutton Lake behind. Photos taken in August.

A wild currant grows here too, just visible behind the serviceberry.

In spite of the tough situation, these shrubs have enough vigor to produce fruit!

A wild currant (red) lies next to where the root enters the ground (click on image to view).

Serviceberries.

Boulder Ridge on the south side of Hutton Lake, Laramie Valley, Wyoming.

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Trees on a Fold

“Forest” on Hutton Lake, next to pale sandstone outcrops. Pattern on lake is windblown waves.

Intent on following my serviceberry tree, neglected since March, I returned to the unexpected forest at Hutton Lake—trees growing where there "shouldn’t" be any. 

Off to see my serviceberry.

The Hutton Lake Forest is the patch of trees on the steep slope across the lake.

Hutton Lake lies in the southern Laramie Basin, in southeast Wyoming. To the east are the Laramie Mountains; the Medicine Bow Mountains lie to the west. The result is a double rain shadow, with the Laramies sucking moisture out of summer storms coming from the plains, and the Medicine Bows doing the same for winter storms from the west. The Basin receives only 11 inches (28 cm) of annual precipitation on average—not conducive to forests. Cottonwoods line the rivers, but the rest of the Basin is covered in grass and shrubs.

Yet on the south side of Hutton Lake stands a charming little forest, with two narrow leaf cottonwoods (Populus angustifolia), a patch of aspen (Populus tremuloides), and about twenty serviceberries (Amelanchier sp.), four of which I consider small trees, being taller than 65 in or 1.65 m (my height). All are growing in a narrow zone less than 100 m long on the northeast slope of a small ridge.

Narrow leaf cottonwood on a windy evening (windy is normal here).

Looking down into the aspen grove. The tilted rocks are a clue as to why these trees are here.

The aspen patch includes about a half dozen trees and many saplings. Aspen readily reproduce vegetatively, via root sprouts, so botanists are quick to conclude that stands are single “individuals” (clones). But there's more than one individual here, for example this tree:

This aspen and several smaller ones nearby are growing out of cracks in the sandstone.

The serviceberry tree that I photographed last March, when it was leafless, is now easy to identify, with its distinctive leaves and fruit.

In spite of the wind, some of these leaves ended up in focus. Click on image to see the distinctive oval leaves with obvious veins and toothed margins.

The berries look like little apples, not surprising given that apples and serviceberries are in the same subtribe of the Rose family (Malinae in the Rosaceae). None were ripe, but some were getting close.

Serviceberries have many names including juneberry, saskatoon, shadblow and others. I wish I could tell you the scientific name of mine, but unfortunately specimens from Hutton Lake have been called both Amelanchier alnifolia and A. utahensis. The two are difficult to separate:

“Serviceberries (Amelanchier spp.) intergrade and hybridize readily, making species identification difficult” (USDA Forest Service).

and:

“Identification is best undertaken in the field, with visits during flowering and fruiting seasons, and observations of habitat, habit, presence of congeners [related species], and flowering time relative to sympatric congeners” (Flora of North America).

Sigh. Maybe I will look into this for a future post, but for now there are much more interesting things to ponder … like the ant hordes.

Little brown dots winding up the right side of the aspen trunk are ants (click on image to view).

There were ants everywhere!—on sandy ground, on sandstone rocks, on aspen trunks growing out of the rocks, and on my bare legs. Fortunately they didn’t bite, but they swarmed up my legs whenever I stopped to take photos and notes.

Why so many ants? Why trees? Maybe the reason is the same—a fold in the land.

When the Laramie and Medicine Bow Mountains were uplifted via massive folds and faults, about 60 million years ago, minor folds were created in the downwarped basin. Hutton Lake lies on the northeast side of such a fold—the Boulder Ridge anticline.

From Ver Ploeg et al., 2016. Added arrow points to exposures of steeply-tilted sandstones

Much of the Boulder Ridge anticline lies out of sight, buried under younger sediments. But erosion has exposed it in places:

“On the south side of Hutton Lake the two limbs of the Boulder Ridge anticline are shown [exposed], the beds on the west side dipping south of west at an angle of 15° and those on the north side dipping north of east at angles of 50° to 85°. The steeply dipping beds … outcrop in a prominent ridge along the south side of the lake.” —Nelson Horatio Darton, 1909

Steep northeast limb (side) of Boulder Ridge anticline. 

Steeply-tilted Muddy Sandstone (lower Cretaceous) behind narrow leaf cottonwood.

Front to back: golden currant, serviceberry, Muddy Sandstone, aspen.

It’s not unusual to find trees associated with rocks in an otherwise unforested landscape. Perhaps there are suitable microenvironments where seedlings were able to grow in the absence of competition from grasses and shrubs. Perhaps there’s more moisture here, from snow drifts, or rain running off tilted rocks. We known that fractures in bedrock serve as reservoirs, funneling and storing water that can be accessed by roots.

As for the ants … well … I don’t know why they were so abundant on the loose sandy soil. Maybe it makes for better burrows. In any case, it appears that they also benefit somehow from the folded rocks of the Boulder Ridge anticline.

Walking back to the car, through the din of complaining prairie dogs, I thought about the little forest and how it came to be. How did seeds manage to land in that little patch of hospitable habitat? How did they hit such a small target? Serviceberry, aspen and cottonwood must cast many seeds far and wide—so many and so far that a lucky few will land in just the right place, even if it’s tiny.

White-tailed prairie dogs are summer company at Hutton Lake. To warn their neighbors of invaders, they chatter and cry loudly … until the invader gets too close at which point they quickly disappear down their holes.

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Sources

Darton, N.H., and Siebenthal, C. E., 1909, Geology and mineral resources of the Laramie Basin, Wyoming: U. S. Geological Survey Bulletin 364.

Knight, DH, et al. 2014. Mountains and plains; the ecology of Wyoming landscapes, 2nd ed. Yale University Press.

Ver Ploeg, A.J., Larsen, M.C., Taboga, K.G., 2016. Characterization of evaporite karst features in the southern Laramie Basin, Wyoming. Wyoming State Geological Survey Report of Investigations No. 70, 34 p.