Monday, September 13, 2021

Green and Red; Stipules and Suckers

In the foreground is skinny Spike, the hawthorn. Behind is Flash, the maple (red canopy).
Since my last report, there has been only a little change in the trees I'm following. Flash's canopy has become even more red, though we've had nothing close to a frost. Spike is still a skinny odd-looking "tree".

Flash has only a few green leaves. The foliage is pretty ragged all in all.
When backlit, the aging samaras (keys) are still beautiful.
For Spike, it is the young leaves that are reddish. The rest are still green.

Now, for botany nerds ...

This month, Spike brought up several botanical terms which I "know" but not really; terms I've heard and even used for decades, but when pressed to explain, can't. At least not confidently. So I asked Google, the expert on everything (we hope).

Stipule: "an outgrowth typically borne on both sides (sometimes on just one side) of the base of a leafstalk (the petiole). Stipules are considered part of the anatomy of the leaf ..."

If you like order, stipule classification is for you! There are types based on many different characteristics, such as duration, shape, size, position, modification, and more. I preferred the summary of function: "Stipules have various functions. Some stipules are not well understood or may be vestigial." This is the way I feel about many things these days.

This hawthorn has foliaceous stipules, i.e., similar to leaves. Being green, perhaps they contribute to photosynthesis—the business of making energy for the tree. I would guess Spike could use the help, having recently recovered from near death. And maybe this is why stipules are more prominent on the suckers (the next topic).

Enlarge to see stipules at base of leaves.
Suckers seem to be universally despised, according to Google. For example, "young stems sprouting from the base or from a spot on the trunk ... are called suckers, because they zap water and nutrients from the main tree. As suckers are unhealthy for trees and they are unsightly, it’s important to know how to eliminate them ..." More here.

The Wikipedia article about Plant Development is more open-minded (see Adventitious structures; Buds and shoots). "Adventitious buds [buds that develop in unusual locations on the plant] are often formed after the stem is wounded or pruned. The adventitious buds help to replace lost branches." I agree! Adventitious shoots are very helpful in this situation.


This is my September report for the monthly gathering of tree-followers kindly hosted by The Squirrelbasket. Worried about another long covid winter? Consider joining us. Tree-following is a good diversion, even in winter, and it's stress-free! More information here.

Tuesday, September 7, 2021

Where on Earth did western Nevada go?

Does the Siberian craton include part of Nevada? (source; text added).
Nevada geologists claim that their state is diverse. I think they're right. On my recent geotrip across the central part, I saw rocks and features dating from Paleozoic time to recent, from the 370-million year old limestone of Devils Gate to a 57-year old fault scarp. However, I saw nothing Precambrian. That's not because Nevada didn't exist then; it did. But now half of Proterozoic Nevada is buried, and the other half is ... GONE!

There are geologists who specialize in running plate tectonics backwards. Using a variety of evidence, they trace the paths of Earth's lithospheric plates to deduce earlier arrangements of continents. They've had some success. For example, there is general agreement that multiple smaller continents (like today) have alternated with a single or several supercontinents. But exactly how continents collided to become a supercontinent, and then how the supercontinent broke up and where the pieces went, are puzzles not easily solved.

A rift runs through it

In the late Proterozoic, roughly a billion to 700 million years ago, Earth's land masses were aggregated into a supercontinent named Rodinia (Russian for "homeland"). Then it broke up into multiple continents and terranes (smaller fragments). The ones that concern us here are Laurentia (predecessor of North America), Siberia (a separate continent then), and Eastern Antarctica.
A reconstruction of Rodinia about 900 million years ago (source); text added.
During Rodinia's breakup, a rift developed across what is now Nevada, from roughly northeast to southwest (modern day compass directions). Eastern Nevada remained part of Laurentia while western Nevada drifted away; they were separated by a widening sea.

Fortunately (for those of us who love such things), the Laurentian coastline is still with us, now called the "0.706 line". It was detected by analyzing many granitic igneous intrusions emplaced long after rifting. The rising magma passed through rocks dating from the time of Rodinia's breakup, and in the process, material from those rocks was assimilated, including two strontium isotopes—87Sr and 86Sr. This is helpful! In continental rocks, the ratio of the two isotopes is greater than 0.706; in seafloor rocks, it is less. So strontium ratios reveal where the late Proterozoic continent and seafloor met.
The 0.706 line (after Kistler & Ross 1990).

Whither western Nevada?

Returning to the original question, where did the continental fragment west of the rift go? Since it was once continuous with eastern Nevada, surely it remains similar in some way—perhaps sharing the same rocks or geological structures. So have geologists wandered the world searching for a similar chunk of continent? Of course they have!

A leading contender resides in the Siberian craton in northeast Asia. The evidence is persuasive. The Sette Daban area of Siberia and the Death Valley area in southwest Nevada share "remarkably similar" sequences of Precambrian sedimentary rocks. In both locations, these "consist of five or six variegated siliciclastic-dolomite cycles that are each made up of numerous smaller cycles ..." (MacLean 2009). Similarity at such a fine scale is compelling.

Furthermore, fossils of the two areas are similar. Especially notable are the trilobites, which usually are limited in distribution. Shared types suggest the two areas were in close proximity. Geologic features are shared as well. Dike swarms and orogenic belts align nicely when the northeast margin of the Siberian craton is placed adjacent to western Laurentia (Sears & Price 1978).
Proposed reconstruction of Rodinia ~ 1 billion years ago (Sears & Price 2003). Shared orogenic belts underlined in red ("NV?" also added).
However, other work suggests that before drifting off, Siberia was joined to Laurentia far north of today's Nevada. For example, McClean et al. (2009) showed that Large Igneous Provinces in northern Laurentia and Siberia are of similar age and chemical composition ... also persuasive evidence!

But of course if we rule out Siberia, we must return to our original question. Where is Proterozoic western Nevada—where did that rifted fragment go?!

Maybe Antarctica?

Goodge et al. (2008) think they've found it in East Antarctica, which is composed largely of Precambrian craton fragments, including rocks not unlike those buried in eastern Nevada. They also cite a boulder (found in a moraine) of a somewhat unusual granite—Type A or rapakivi. It is similar to a zone of rapakivi granites that crosses North America/Laurentia, dated at ~1.4 billion years.
Rodinia 750 million years ago; red dots are ~1.4 Ga rapakivi granites (Goodge et al. 2008) ("NV?" added).
But more work is needed. Most bedrock of Eastern Antarctica is covered in ice year round. It's difficult to get a comprehensive picture from corings and rocks in moraines.

Next question

While the plate reconstructionists haven't yet answered our question as to whither, we do know that Proterozoic western Nevada is gone. Furthermore, the growing ocean that separated it from Laurentia has disappeared too. So what makes up western Nevada now? Stay tuned.
Pine Nut metavolcanics in western Nevada—a traveler come to rest.

Sources

DeCourten, F. 2003. The Broken Land; adventures in Great Basin geology.

DeCourten, F and Biggar, N. 2017. Roadside Geology of Nevada.

Goodge, JW, et al. 2008. A positive test of East Antarctica-Laurentia juxtaposition within the Rodinia supercontinent. Science 321, 235–240.

Kistler, RW, and Ross, DC. 1990. A strontium isotopic study of plutons and associated rocks of the southern Sierra Nevada vicinity. USGS Bull. 1920.

MacLean, JS, et al. 2009. Detrital zircon geochronologic tests of the SE Siberia-SW Laurentia paleocontinental connection, Stephan Mueller Spec. Publ. Ser., 4, 111–116, https://doi.org/10.5194/smsps-4-111-2009 

Piper, JD. 2011. SWEAT and the end of SWEAT: the Laurentia–Siberia configuration during Meso-Neoproterozoic times. Int. Geol. Review 53.

Sears, JW, and Price, RA. 1978. The Siberian connection: A case for the Precambrian separation of the North American and Siberian cratons: Geology 6: 267–270.

Sears, JW, and Price, RA. 2000. New look at the Siberian connection: No SWEAT. Geology 28.

Sears, JW, and Price, RA. 2003. Tightening the Siberian connection to western Laurentia, Geol. Soc. Am. Bull. 115.

Thursday, August 26, 2021

The Snowy Range, 2 billion years in the making

Medicine Bow Mountains and the Snowy Range rise above the Laramie Plains.
In the early 1980s, author John McPhee was gathering information for a book, Rising from the Plains, about Wyoming geology. He crossed the state on Interstate 80 from east to west, in the company of one of the grand old men of Wyoming geology, the late John David Love. McPhee took notes while Love drove and expounded on the landscape.

Near Laramie, as they looked west at distant mountains, McPhee was struck by the illusion: "... the Medicine Bow Mountains and the Snowy Range stood high, sharp, and clear, each so unlike the other that they gave the impression of actually being two ranges ... the flat-crested Medicine Bows, dark with balsam [subalpine fir], spruce, and pine; and, in the far high background, the white and treeless Snowy Range."

In fact, the latter sits atop the former, and geologically they are one.

Ancient sediments

In 1868, just a few months after Laramie was established, Arnold Hague of Clarence King's Fortieth Parallel Survey became the first geologist to explore the Medicine Bows. In his 1877 report, Hague described a flat-crested mountain range with "elevated plateau country, nearly 10,000 feet above sea-level ... dotted over with numerous alpine lakes." From this high surface rose a sharp-edged ridge that "culminates in Medicine Peak, a grand, broad central mass." [The plateau country is now Libby Flats, the ridge the Snowy Range, and the high point Medicine Bow Peak.]

The Snowy Range on the horizon, above Libby Flats.

"... the amphitheatres, with mural faces 1,500 feet deep, cut out of pure white quartzite, are very striking," wrote Hague. The peak itself "is a mass of pure white quartzite, rising nearly 2,000 feet above the surrounding country ..." He assigned the quartzite to what was then called the "Archean series"—the oldest rocks on Earth, specific age unknown. At that time, it was the best a geologist could do.

Hague found layers of pebbles and other signs of bedding in the quartzite, convincing him it had started as deposited sediments. He also concluded that the beds, originally horizontal, had been steeply tilted. But if he had further thoughts about how the quartzite and ridge formed, he didn't share them.
Pebbles in quartzite, cited by Hague as evidence of sedimentary origins.

Two decades later, a geology graduate student from the University of Wisconsin, Charles Van Hise, crossed the Medicine Bow Mountains on horseback in just three days. During his brief visit, he examined the rocks at the crest, taking notes for his PhD dissertation about North America's Precambrian rocks (equivalent to "Archean series" used by Hague). Like Hague, he described the quartzite as ancient and sedimentary.

Neglected no longer

In 1917, a third geologist came to southeast Wyoming to study the Medicine Bow Mountains. "Dr. Eliot Blackwelder, head of the department of geology at the University of Illinois arrived in this city this morning ..." reported the Laramie Boomerang on July 24. He would "start on a geological expedition in the Medicine Bow mountains in a few days." Blackwelder was interested specifically in the ancient rocks at the crest.

Blackwelder found the Medicine Bows a wonderful place to work, as he explained in his report. "In spite of its ready accessibility, this interesting range has been strangely neglected by geologists until the last decade. ... no detailed work seems to have been attempted." He would fill that gap, spending six weeks in the range in 1917, and a month in 1925.

At the end of 1926, Blackwelder published his Precambrian geology of the Medicine Bow Mountains. He named the "great, massive quartzite" of the Snowy Range the Medicine Peak quartzite, describing it as "extraordinarily thick"—on the order of 5600 ft! He too concluded it consisted of metamorphosed sediments dating from Precambrian time (but still without a specific age). Unlike his predecessors, however, Blackwelder offered a probable scenario for its origins.
Cross-section through the Medicine Bow Mountains in the area of the Snowy Range. Note the thickness of the Medicine Peak quartzite! (labeled "D"). Blackwelder 1926.
 Medicine Peak quartzite above Mirror Lake. Added arrow points to a huge dike—magma injected into the quartzite. Blackwelder 1926.

Reading the rocks

The Medicine Peak quartzite started as quartz sand, became sandstone, and then was metamorphosed under intense pressure to its final form—very hard rock that sparkles in the sun. Yet it still provides clues about its ancient birth. Blackwelder often spotted ripple marks and cross-bedding (layers at angles), evidence that the sand had accumulated in shallow active water. He suggested it was deposited just offshore, where it would be shaped by waves, or streams flowing into the sea.
Cross-bedding preserved in Medicine Peak quartzite; block is about 1 m long.
And yet the quartzite was so thick—at least 5600 ft even after compaction and metamorphism! How could so much sand accumulate in shallow water? Blackwelder turned to a modern-day analogy. "The great thickness of pure quartzite represents sifted sand that might have been deposited and worked over on a marine shelf, like that around Cape Hatteras, on the Atlantic coast of the United States."

But if so, how did sand on a marine shelf become quartzite 11,000 ft above sea level, far from any ocean? In Blackwelder's day, there was no good answer for this kind of question. It would be almost 40 years before enlightenment arrived.

Earth's dancing plates

By the early 1960s, geologists had accumulated enough evidence to put forward the theory of plate tectonics, now widely accepted. The Earth's rigid outer shell, the lithosphere (crust and upper mantle), consists of giant "tectonic plates" that grow, break, stretch, compress, dive under, thrust over, and collide in a slow but powerful dance. In the process, landscapes are changed on a grand scale.
Earth's plates (source)—very different from 2 billion years ago.
It was the movement of tectonic plates that created the Snowy Range. Here's the basic plot: Along the Wyoming coast, a massive amount of sand accumulated offshore. A plate collision pushed up mountains, metamorphosing and tilting the sand(stone). These mountains were worn down, their remnants buried. Then another tectonic confrontation pushed up the Medicine Bow Mountains. Erosion exposed the ancient quartzite and shaped the Snowy Range.

The former world

The Medicine Peak quartzite started as sand 2.1 billion years ago. Back then, Wyoming was part of Superia, a smallish supercontinent. But Superia was coming apart, leaving Wyoming on the coast of a growing ocean. Sand and other sediments would accumulate just offshore for some 200+ million years.
Modified from Mitchell and others, 2021.
Then something changed, something huge! Exactly what may be lost to deep history, or maybe not yet discovered. In any case, the widening ocean disappeared.

Collision and a continental suture

In their studies of the quartzite, Hague, Van Hise, and Blackwelder all could see that the beds of sand, which were horizontal when deposited, were now far from it. "In general the sedimentary beds are nearly vertical or steeply inclined to the southeast," wrote Blackwelder. They had been tilted almost 90 degrees!

The cause was continental collision. About 1.78 billion years ago, a smallish tectonic plate called the Green Mountain Terrane bumped up against the Wyoming coast. This "collision" went on for 40 million years, producing among other things a continental suture called the Cheyenne Belt—a zone of highly deformed rocks.
Inferred location of the Cheyenne Belt, a continental suture (original source unknown).
Deformed rock of the Cheyenne Belt, Medicine Bow Mountains (field trip stop 1); ruler is 15 cm.
As is typical for such a collision, a mountain range was pushed up, tilting the sand-turned-to-quartzite on its side. But that mountain range is now mostly gone. Though they may seem permanent to us, mountains too have lifetimes. As soon as they rise, erosion goes to work wearing them down, sometimes burying them in their own debris.

The remnants of the ancient range would lie buried for hundreds of millions of years, while sediments accumulated to great thickness. The quartzite would be covered by tens of thousands of feet of limestone, sandstone, and shale by the time the next big change arrived.

West Coast happenings impact Wyoming

That change was uplift of the Medicine Bow Mountains. It happened during a great mountain building event called the Laramide Orogeny, which started 80 million years ago, lasted almost 40 million years, and created mountain ranges from Mexico to Canada—the Rockies. In contrast with the previous collision, the plate jostling this time was remote. Almost a thousand miles to the west, the oceanic Farallon plate was diving under the North American plate, compressing the continent and pushing up mountains far inland.
Rocky Mountains due to subduction far to the west (source). 
Of course, as soon as the Medicine Bow Mountains rose, erosion set in. Eventually enough of the sedimentary rock cover was removed to expose the ancient Precambrian core. Being super hard and durable, the Medicine Peak quartzite eroded much more slowly, and was left as a high-standing ridge.

As Eliot Blackwelder would write 40 or 50 million years later, "The Snowy Range owes its prominence and position to a great, massive quartzite formation."

Field trip—you too can read the rocks!
The Snowy Range at the crest of the Medicine Bow Mountains, just 50 miles west of Laramie.
This tour includes five stops—four at the crest and one en route. Start early to include a hike to the summit of Medicine Bow Peak.

Zero your odometer at the junction of Highways 130 and 230 in West Laramie, and drive west on 130. At about 19.5 miles, as you descend into the Centennial Valley, slow down to take in the view. Immediately ahead are the forested Medicine Bow Mountains. Seemingly behind and above is the Snowy Range. Even this close, the illusion persists.

1. At 36 miles, turn right and park along the Brooklyn Lake Road near Nash Fork Campground. To view a bit of the 1.78 billion year old continental suture, walk into the campground, stay left on the loop, and just past the fee station and site 27, walk left (west) 20 or 30 yards to dark rock above the highway. Look around your feet for fine laminations, with waves and tight chevrons created by continental collision. Then check the two huge white quartzite boulders (dropped here by glaciers) for cross-bedding from deposition offshore, and gray bands with white pebbles flattened during collision.

2. At 40 miles, visit Libby Flats observation point (with restrooms and a "castle"). Enjoy Arnold Hague's "elevated plateau country ... dotted over with numerous alpine lakes."

3. A quarter mile farther west on Hwy 130, turn left to Medicine Bow Peak Over Look, with helpful interpretive signs. On the Snowy Range diagram, find The Diamond with Mirror Lake below—location of Blackwelder's photo included here, and the next stop.

4. Continue west 1.3 mile to Mirror Lake Picnic Area. Near the entrance, compare your view with Blackwelder's photo. In looking at the spectacular face, remember ... it is beds of sand turned vertical! From the high point of the loop, examine the large dark dike (marked in photo)—magma injected into the quartzite while it was still underground.

5. Continue west a short distance to the first of two Lake Marie parking lots. At the east end, explore the field of white quartzite boulders. Bedding and cross-bedding are common. Search to find gray bands with flattened white pebbles, evidence of plate tectonics in action!

A short distance farther on the highway is the west Lake Marie parking lot and a trailhead for Medicine Bow Peak, 12,013 ft elevation. The round trip is 8 or 9 miles. A shorter trail leaves from Lewis Lake, but doesn't have as much wonderful scenery in my opinion. A loop can be done to include both (see maps online).
Cross-bedded quartzite en route to Medicine Bow Peak from west Lake Marie trailhead.
Summit of Medicine Bow Peak—a giant pile of quartzite boulders.

Sources

Blackwelder, E. 1926. Precambrian geology of the Medicine Bow Mountains. Bull. Geol. Soc. Am. 37:615–658.

Hague, A. 1877. Medicine Bow Range, in US Geological Exploration of the 40th Parallel, vol. ii: 94–111. Washington, DC: GPO.

Hausel, WD. 1993. Guide to the geology, mining districts, and ghost towns of the Medicine Bow Mountains and Snowy Range Scenic Byway. WSGS Public Information Circular 32. Free PDF.

Sullivan, WA, and Beane, RJ. 2013. A new view of an old suture zone: evidence for sinistral transpression in the Cheyenne belt. GSA Bull. 125:1319–1337.


This post is based on my recent contribution to the History column of the Laramie Boomerang, which features articles by volunteers eager to share our local history. We also hope to relieve the dismal monotony of pandemic news, and support our flagging local newspaper! Articles are archived at the Albany County Historical Society website.


Tuesday, August 17, 2021

Frank Tweedy's Traveling Plants: WY to NYC & back

Frank Tweedy. Union College Special Collections (used with permission); date unknown.
Readers of this blog may remember Frank Tweedy of the US Geological Survey, who surveyed the Laramie Plains in 1892 (Mapping the Laramie Plains, 3rd dimension captured). In August of that year, the Laramie Boomerang announced that Tweedy and assistant James McFarland would "commence work upon the topography of this section of the country." Three years later, the "Laramie Sheet" was published—one of the first topographic maps for Wyoming.

In January of 1903, there again was a Frank Tweedy in the Laramie news. "Prof. Nelson [University of Wyoming] has received a rare collection of plants from Mr. Frank Tweedy ... a botanist of considerable distinction" reported the Republican. Were USGS surveyor Frank Tweedy and distinguished botanist Frank Tweedy one and the same? And how did 700 plants survive a trip to Laramie in January?!

Dead, flat, & dry

Actually, survival was not an issue, for these plants were already dead. But they still were of great value. All were collected in 1900 in the wilds of the northern Bighorn Mountains. There they were carefully arranged in paper folders so that parts needed for identification were visible, and placed in a plant press with absorbent felt sheets until dry (several days to several weeks, depending on weather).

After the field season, they made their way east, ending up at the New York Botanical Garden where the great botanist, Per Axel Rydberg, either identified them, or, if they were new to science, named them himself. Then in 1903, "upward of 700" traveled west to Laramie, each accompanied by a label with the plant's name, collection location, date, and collector—Frank Tweedy.

At the university there was more processing, for dried plants are fragile, and won't last long if left loose in paper folders. They were mounted on 11" x 18" sheets of durable paper, preserving them for centuries to come, and properly filed in the university herbarium.

Pleated gentian, Gentiana affinis, collected by Frank Tweedy in 1900. Rocky Mountain Herbarium.

Herbarium?

If you don't know what a herbarium is, you're not alone. Few people do. Many think it's some kind of greenhouse, but actually it's the opposite—a collection of pressed dried plants. The first, called a "hortus siccus" (dry garden), was created in the 1520s by Italian botany professor Luca Ghini. He wanted a way to teach plant identification in the winter, so he pressed and dried plants, and glued them to paper sheets. Fed up with their ancient textbooks, Ghini's students loved him for it.

Today, students still use herbarium specimens to learn to identify plants. But they took on a much bigger role during the golden era of global exploration (16th–19th centuries)—documentation of the world's flora. Herbaria proliferated and flourished. Now there are at least 3300, holding nearly 400 million pressed dried plants!

New herbarium grows fast

By 1892, the University of Wyoming had been operating for five years with a botany professor (Aven Nelson) but no herbarium! This was unacceptable for the state's only university. Fortunately, Experimental Station Supervisor Burt C. Buffum had collected Wyoming plants for several years, accumulating on the order of 500. Several hundred were set aside for an exhibit at the 1893 World's Columbian Exposition in Chicago. As for the rest, University President Albinus Johnson directed Nelson to use them to start a herbarium.

Nelson knew little about plant identification and herbarium management, but that didn't slow him down. In 1899, he launched an ambitious project. For 14 weeks, he traveled Yellowstone Park by horse-drawn wagon, with his wife, two daughters, and two students. They collected zealously, returning to Laramie with 30,000 specimens! Most were duplicates, to be sold or traded to fund and expand the UW herbarium.

Collecting plants in Yellowstone, 1899. Photo by Aven Nelson; American Heritage Center (AHC).
Before the trip, Nelson wrote to his esteemed colleague Per Axel Rydberg at the NY Botanical Garden, asking where in Yellowstone he should collect. Rydberg replied: "The flora of the park is, however, well worked up as several collectors have been in there ... The one that has done the most, however, is Frank Tweedy of US Geological Survey. He spent two whole summers in the park."

Indeed, surveyor Frank Tweedy and botanist Frank Tweedy were one and the same!

An eye for novelty

Frank Tweedy was born, raised, and educated in New York, graduating from Union College in 1875 with a degree in civil engineering. He began his surveying career the next year in the Adirondacks, followed by a stint as a sanitation engineer in Rhode Island. All the while, he collected plants.

If we follow Tweedy's trail of herbarium specimens (accessible online), we go from New York to New Jersey to Rhode Island. But then we make a huge leap west. In 1882, Tweedy went to work as a topographer on the Northern Transcontinental Survey in Washington Territory. And he collected plants.

For Tweedy, this was a very different kind of botanical world, largely unexplored and rich in novelties—species new to science. He collected his first that summer, a grass from the Wenatchee Mountains. It was named Tweedy's reedgrass (Calamagrostis tweedyi) by grass expert FL Scribner, who wrote: "Mr. Tweedy has been a careful and zealous collector of the plants of the various sections of our country which he has visited, and it is with pleasure that I dedicate this species to him."
Calamagrostis tweedyi, Tweedy's reedgrass, from American Grasses (FL Scribner 1897).
This was the first of more than 100 plant species discovered by Tweedy, and the first of at least 35 named in his honor. By the time his specimens arrived in Laramie in 1903, he was a highly-regarded pioneering botanist of the American West.
Erigeron tweedyi, Tweedy's fleabane. Photo by Matt Lavin (Flickr).

Herbarium in the news

Meanwhile the UW herbarium had grown rapidly, thanks to collecting by Nelson and his students, and acquisitions through purchase and trade. In 1899, he convinced the University Trustees to make it a separate institution—the Rocky Mountain Herbarium (as it is today), with Nelson as curator.

Within a few years, Nelson and the Rocky Mountain Herbarium had become newsworthy. In May of 1902, the Rawlins Republican reported "[a set] of 800 Wyoming plants has just been forwarded to the Carnegie museum (Pittsburg) by Professor Nelson" who also "received an interesting collection of plants, some 300 in number, from Dr. Riser of Rawlins ...". Even more notable, Nelson shipped a collection of potentillas (cinquefoils) to Germany, to "Dr. Theodore Wolf, a German botanist, who is preparing a monograph of all the species of the genus in the world." In exchange, German potentilla specimens would be sent to the Rocky Mountain Herbarium.

In July, the Cheyenne Daily Leader had exciting news. "12,000 Specimens of Rare Herbs and Plants for the State University" had been collected in Nevada, New Mexico, Utah, and Wyoming by Leslie Goodding, one of Nelson's students. About 800 species were represented, including every botanist's dream—species new to science (several were named in Goodding's honor).
University of Wyoming, 1901. AHC, SH Knight Collection.
According to the Laramie Boomerang, by September of 1902, UW's herbarium contained 36,000 specimens—impressive given there were still just three buildings on campus (not counting barns and greenhouses). At the end of the year, when Nelson's articles about saltbushes and hawthorns were published in the University of Chicago's Botanical Gazette, the Laramie Republican proudly and rightly declared, "Prof. Nelson is a recognized authority on Rocky Mountain and western plants."

Thus we shouldn't be surprised that a botanist of Tweedy's caliber would contribute a "rare collection of plants" to the Rocky Mountain Herbarium.

Imagining the past

During my research, I often imagined Tweedy and Nelson in conversation—the renowned western botanist encouraging Nelson's ambitions. Did they meet when Tweedy was surveying the Laramie Plains in 1892? Or maybe they made arrangements in May of 1901, when the Personals section of the Boomerang reported that "Frank Tweedy of Washington is in the city" (no further details).

I searched and searched for correspondence between the two men, eager to find a climax for this story. Instead, I discovered that the Republican, or perhaps Nelson, had led me astray.

In examining Tweedy's specimens at the Rocky Mountain Herbarium, I discovered a puzzling label on the lower left corner of each: "Received from A.A. Heller, 1903". As I would learn, Nelson didn't receive the specimens directly from Tweedy. He bought them from Amos Arthur Heller. (Heller probably got them through a trade, but we can't be sure.)

A fantastic bargain just the same

Heller was an American botanist active from 1892 to 1940. The standard botanical sources include his professorships in Minnesota, California, and Nevada, as well as work for prominent botanical institutions. But I knew nothing of his stint as a freelance plant dealer until I visited UW's American Heritage Center, where I found a folder of letters from Heller to Nelson. 

On December 3, 1902, Heller wrote Nelson from Puerto Rico: "If you care for them, I have a collection of 700 Wyoming plants collected by Frank Tweedy, which I will sell for $45.00. There are a lot of new species among them [named] by Rydberg, and I understand he [identified] the whole collection. I am giving you the first chance at these, as I know they will be of more value to you than any one else." He then advised, "If you want the Wyoming plants, Mrs. Heller [in Pennsylvania] will attend to sending them."

Apparently Nelson jumped at the opportunity. In a letter dated December 29, E. Gertrude Heller wrote: "I will ship you the plants at once ...", which she must have done since they arrived sometime before January 14, when their story appeared in the Laramie news.

Surely Nelson was happy with his purchase—nearly 700 specimens representing 500+ species, collected by a highly-respected botanist. And, as the Republican explained, "As not more than three of these sets of plants are in existence this herbarium is fortunate in securing one" (the others went to the National Herbarium and the NY Botanical Garden).

Furthermore, "since [Tweedy's] work carries him into many places, inaccessible to the ordinary collector, his plants are unusual and interesting." Here the Republican was correct. A dozen of the specimens were species new to science! Obviously Frank Tweedy was very good at spotting botanical novelties, even while surveying.
Tweedy's gilia (Gilia tweedyi), collected by Frank Tweedy in the Bighorn Mountains. Dried plant is about 8 in tall. H. Marriott photo; added flower photo by Matt Lavin, 2012 (Flickr).

🌺🌼🌾

This post is based a recent contribution to the History column of the Laramie Boomerang, which features articles by volunteers eager to share our local history. We also hope to relieve the dismal monotony of pandemic news, and support our flagging local newspaper! Articles are archived at the Albany County Historical Society website.

For more about Frank Tweedy, perhaps our most under-appreciated pioneering botanist, see his Wikipedia page. It was created just last year by this author (herself a botanist), and Noel Sherry, who is exploring Tweedy's mapping, plant collecting, and more.

Saturday, August 14, 2021

Tree-following: Red and Green


Both trees I'm following this year are red and green, but in different ways. Last month, Flash the maple was covered in green leaves and red samaras. The samaras are still red but looking duller. And the leaves are starting to turn red. It hasn't been cold, not even close. Could this be due to heat and smoke? Or maybe just normal life for Flash.

Spike the hawthorn still has rich green leaves, while the young emerging leaves are reddish. No flowers or fruit this year, but that's fine. Having nearly died (or so it looked!), Spike is to be commended for the healthy shoots and foliage.

Fresh young hawthorn leaf, with ant.


This my contribution to the August gathering of tree-followers. Thanks to The Squirrrelbasket for hosting!

Saturday, July 17, 2021

A "Peculiar" Miner's Candle

Miner's candle; southern Laramie Mountains, Wyoming.
In 1869, botanist Benjamin Hayes Smith of Denver, Colorado Territory, collected a plant with a tall straight inflorescence, the small clusters of white flowers subtended by prominent leafy bracts. Did he think it unusual? We don't know.

Smith gave it and other plants he collected in the Denver area to Thomas Conrad Porter, botanist with the Hayden Expedition of 1869, who did consider it noteworthy. He described and named it as a new species in Hayden's 1871 report.

Like me, Porter was impressed with the inflorescence. "... cymis plurimis in axillis foliorum conglomeratis pedunculatis superne subsessilibus confertisque;" he wrote in the obligatory Latin, before explaining that "the stout virgate spike made up of numerous glomerate cymes, crowded in the axils of the linear cauline leaves, which much exceed them in length" was unusual enough that "I have ventured to give it a name." He chose Eritrichium virgatum, in reference to the inflorescence. (Virgate means long, straight, and slender.)

The inflorescence takes up most of the plant! 

Below each flower cluster is a long leafy bract, or leaf if you prefer.

Over the next half century, taxonomists would revise the section of the borage family containing this species several times, moving it from genus to genus, often noting the distinctive inflorescence. In 1885, the great Asa Gray called it Krynitzkia virgata. "The slender leaves subtending the cymes of the virgate thyrsus are an inch or two long, all but the uppermost several times longer than the flower-clusters."

Two years later, Edward Lee Greene put it in Oreocarya. And finally, in 1927, Edwin Blake Payson of the University of Wyoming moved it to Cryptantha, where it remains today. He wrote: "The strictly erect, rod-like stems with the closely set white flowers are unique. The numerous elongated leaf-like bracts add to the peculiar appearance and serve to separate the species from its relatives." That's another reason I like this plant. Not only is it stunning when in bloom, it's easy to identify! (Cryptntha is a genus notorious for id challenges.)

"elongated leaf-like bracts add to the peculiar appearance" (photo by Patrick Alexander 2011).
Spectacular hairs, common in the Boraginaceae, make a 10x hand lens a good investment! (Patrick Alexander).
Surely such a distinctive plant would have a fitting common name. But no. The sources I checked all call it "miner's candle", which also applies to several close relatives. (If you know of another, please leave a Comment.)

Also peculiar is the distribution of this miner's candle. It's restricted to rocky slopes at lower elevations in the Rocky Mountains of Colorado and southeast Wyoming. In Plant story: miner's candle, Cryptantha virgata, wandering botanist Kathy Keeler finds this odd. "The Rocky Mountains extend 3000 miles (4800 km) from northern British Columbia in Canada to New Mexico in the southern United States, so there would seem to be a lot of similar terrain where miner's candle could grow. But it doesn't."

Cryptantha virgata (Rocky Mountain Herbarium, U WY)

But there's more to distribution than potential habitat. Seeds have to get there, seedlings have to survive. Maybe the distribution of Cryptantha virgata is limited because it hasn't dispersed to all potential habitat ... yet. Maybe it's only recently evolved, and now is slowly spreading.

The Denver area in 1869, by William Henry Elliott of the Hayden Expedition.

Sources (most available online at Biodiversity Heritage Library)

Elliott, Henry W. Sketches made by the artist of the Geological Survey of Colorado & New Mexico. US Geological Survey Open-File Report 03-384. PDF

Gray, A. 1885. Proceedings of the American Academy of Arts and Sciences 20: 279.

Greene, E.L. 1887. Pittonia 1: 58.

Hayden, F.V. 1871. Preliminary Report of the United States Geological Survey of Wyoming and Portions of Contiguous Territories: 479–480 [in Porter's Catalogue of Plants].

Payson, E.B. 1927. A monograph of the section Oreocarya of Cryptantha. Annals of the Missouri Botanical Garden 14: 270.

Williams, R.L. 2003. A Region of Astonishing Beauty: The Botanical Exploration of the Rocky Mountains. Roberts Rinehart