In the strange landscape of Colorado’s high alpine tundra, most life stays small to survive. Tiny wildflowers spring from meager soil, accompanied by mosses and lichens adapted to the thin air and blistering cold. But bursting from scree slopes in the high Rockies of central Colorado grows a mighty thistle, often nearly 3 feet tall, topped by a dense head of fuzzy yellow flowers.
It has a new name: the funky thistle.
The thistle was one of two described as a distinct species for the first time in a recent study by Jennifer Ackerfield, who heads the natural history collection at the Denver Botanic Gardens. Named for Ackerfield’s botany mentor Vicki Funk, the thistle and its cousin Cirsium culebraensis, could help researchers understand how climate change is altering Colorado’s ecology.
“If you’ve seen the funky thistle, you’ll never forget it,” Ackerfield said. It stands out on the barren landscape above treeline, particularly when its wooly flowers bloom from late July to early August. Bumblebees often nestle into its fur-like heads for warmth overnight, and pikas — small high-mountain mammals — can be seen scurrying back to their burrows with mouthfuls of the thistle’s spiny leaves.
But for more than 150 years, the funky thistle was lumped in with the mountain thistle, a more common and widespread variety. The first specimens were collected in 1862 by botanist Charles Parry, whose examples, once dried out for preservation by another researcher, became hard to distinguish from the mountain thistle, and remained mislabeled in collections for decades.
Ackerfield and other researchers, however, started to notice Colorado’s high mountain thistles can show a lot of variety. Blooms can range from pink to purple to white or yellow. The shape of branches and leaves can vary widely. In recent years, researchers discerned three distinct species of mountain thistle. Ackerfield’s discoveries, the funky thistle — technically Cirsium funkiae — and its cousin Cirsium culebraensis, found in the Culebra Range southwest of LaVeta, are numbers four and five.
The funky thistle is so far only known to exist almost entirely above treeline in central and southern Colorado, stretching from near Quandary Peak south into the Sangre de Cristo mountain range, and in one isolated population near Santa Fe. The variety in the Culebras is not known to appear anywhere else.
Watching these populations over time, and looking back on older specimens with new information, could have an impact on the knowledge of life in Colorado’s high country.
A “new lens” on climate change
Ackerfield’s thistles join nearly 70,000 other preserved plant specimens representing thousands of species in the Kalmbach Herbarium at the Denver Botanic Gardens. With specimens dating to the 1850s, the herbarium is part of a network of research collections in several states that chronicle the biodiversity of the West.
“Each specimen is a snapshot of a moment in time,” Ackerfield said. “As herbaria have grown and connected with each other, we now have billions of snapshots from all over the world, some going back centuries. We can use that to answer all kinds of questions.”
The Kalmbach Herbarium’s specimens have already yielded startling data: Colorado’s high alpine plants are blooming on average a month earlier than in the 1800s, with some species near Grand Junction and in South Park blooming a full 42 days earlier.
“It’s climate change, and it’s real,” Ackerfield said. “The proof is in our cabinets.”
Discerning new species, like the two thistles, can deepen researchers’ understanding of changes in a delicate ecosystem like the high alpine environment, said David Anderson, who heads the Colorado Natural Heritage Program at Colorado State University, which studies rare plants in need of conservation.
Once a new species is described, its geographic range and ecological niches can be determined, and then observed over time.
“It’s a new lens through which to look at climate change,” Anderson said. “How is this species affected? Will its range move further north, or to different elevations as the climate warms? How are the species associated with it changing?”
Colorado’s high alpine environments are unique from a conservation standpoint because they’re largely on federal land and better protected from development than lower elevations, where shortgrass prairies face pressure from agriculture and oil and gas extraction, Anderson said. But species growing in the high alpine are far more vulnerable to a warming climate because they often can only exist in narrow ranges of temperature, moisture and soil conditions.
“Looking at these thistles, they’re huge plants compared to most of the other species at that elevation,” Anderson said. “They play a crucial role as a food source for pollinators, and pollinators support the rest of the ecosystem, including people. But pollinators are in trouble, with some species of bumblebees facing extinction. What do these thistles and those pollinators mean to each other?”
Monitoring species through herbarium data is becoming increasingly crucial, Anderson said.
“Things are changing so fast in Colorado,” he said. “We’re trying to get a handle on it. As the climate warms and people push into different habitats, many species will have to move around and realign themselves. There will be winners and losers.”
Both the funky thistle and the variety in the Culebras could be among the winners, thanks to their abundance and relative stability, according to Ackerfield’s research. Many species aren’t so lucky.
“The really rare plants are the most vulnerable,” Anderson said. “They live on tiny postage stamps of environments. There’s a little penstemon that lives on the cliffs above Parachute, close to a lot of oil and gas activity. Its habitats are so tiny that as the planet warms, it’ll need to move, but it won’t have anywhere to go.”
Colorado likely has many species of plant and animal life yet to be discovered, Anderson said.
“New discoveries actually happen somewhat regularly,” he said. “Sometimes it’s something like this, where a species has been hiding in plain sight and not yet recognized, but sometimes it’s stumbled upon.”
A CSU researcher discovered a “really weird” snakeweed in Lone Mesa State Park in southwestern Colorado in the 2000s, Anderson said.
“When you include insects like moths and beetles, I’m confident there are hundreds of undescribed species in Colorado,” Anderson said.
“I’ll be huge and be out here”
Ackerfield said describing the two thistle species is a thrilling moment in her career, though intimidating.
“There’s an umbrella of imposter syndrome in everything a scientist does,” she said. “Am I right? Will someone come along and tell me I don’t know what I’m doing? I haven’t gotten any pushback yet, so now I’m allowing myself to get excited.”
Ackerfield has studied botany in the Colorado Rockies for more than 30 years, and said thistles always stood out.
“The alpine is dominated by itty-bitty plants,” she said. “Thistles come along and say, whatever, I’ll be huge and be out here. I don’t need to be tiny.”
Thistles are part of the aster family, one of the most abundant on earth. They have prickly spines and an arrangement of flowers in one head, called a capitulum. To determine the validity of the new species, Ackerfield studied the plants’ DNA profiles and the form and structure of their component parts.
Ackerfield is careful to say that she described new species, not that she discovered them, because she says it’s entirely possible that Indigenous people had distinct names or uses for different species, perhaps only now being rediscovered by contemporary researchers.
Ackerfield began her research on Colorado’s mountain thistles as part of her Ph.D. studies in 2016, where she met Funk, an influential botanist at the Smithsonian Institution.
Funk was, well, funky. She was a world-renowned researcher with a penchant for Hawaiian shirts and a willingness to get out on the dance floor at conferences. Ackerfield recalled her habit of singing to herself when pricked by thistle spines: “Ooh ee, ooh ah ah, ting tang, walla walla bing bang!”
“Once it started becoming apparent I was looking at new species, I knew I had to name the funkiest one after her,” Ackerfield said.
After years of largely lab-based research, the time came in September 2020 to collect the representative samples of the funky thistle that would be entered into the herbarium. Ackerfield invited several scientist friends to join her on an expedition to the slopes of Mount Sherman, a fourteener near Leadville where the species is plentiful and accessible.
“It was six months into COVID, and everyone was just dying to get outside,” she said. “It was one of those beautiful fall days in the alpine, with blue skies and crisp air.”
After the team collected their samples, Ackerfield thought of her boisterous mentor as she busted out a case of beer. Funk passed away in 2019, too soon to see Ackerfield’s research completed.
“I’m sure she’d tell me she didn’t need a species named after her,” she said, “but how could I not?”