Cloning It In: The Weird and Wonderful Life of the Rocky Mountain Monkeyflower

“Why’s it called the monkeyflower?” I asked as we hiked along a flat, even trail, keeping a relaxed pace and saving energy for the more rugged terrain to come. Savanna Smith, Colorado Parks and Wildlife’s (CPW) Rare Plant Program Manager, speculated that it may be because the flower’s pale color looks like the face of a monkey. “I could maybe see that,” she said. 

“I’ve heard that it’s because the flowers resemble a monkey’s face … just the shape,” said Mark Beardsley, an ecologist for EcoMetrics, with a hint of skepticism in his voice. “It almost looks like a clown to me.” 

When I look at the silhouette of the monkeyflower, with its frond-like petals, I don’t see the visage of a snub-nosed monkey or a pig-tailed macaque — I see a spider holding its arms up like it’s on a rollercoaster, but that’s just me.

Savanna, Mark, Kara Van Hoose — CPW’s Northeast Region Public Information Officer — and I were heading into a remote part of Staunton State Park to search for populations of the Rocky Mountain monkeyflower, a one-of-a-kind rare plant. This species of monkeyflower (there’s a whole genus of them) is endemic to Colorado, meaning it’s found here and nowhere else. Facing an uncertain future, it’s included in Colorado’s State Wildlife Action Plan (SWAP). 

The SWAP is a broad plan that sets conservation priorities for specific species and their habitats. A ranking system scores each species based on the current health of its populations and its susceptibility to existing or potential threats, such as habitat loss, disease, lack of research and others.  Each Species of Greatest Conservation Need (SGCN) is ranked as Tier 1, Tier 2 or Species of Greatest Information Need (SGIN). All 50 states publish a revised and updated SWAP every 10 years, setting new priorities according to what’s changed. When SWAPs are revised, species can be added, removed or moved to a different ranking. Colorado’s SWAP is currently under revision, and CPW is taking feedback from the public before submitting its draft to the U.S. Fish and Wildlife Service for final review. The public comment period ends on Aug. 8. Comments can be submitted via Engage CPW website.

The Rocky Mountain monkeyflower is ranked as Tier 1, putting it among other species in the most urgent need. With very specific habitat requirements and an unusual survival strategy, the flower is a high priority for Colorado botanists, ecologists and conservationists.

Monkeyflower business

The life of a Rocky Mountain monkeyflower is short, precarious and peculiar. It’s an annual plant, meaning it only sprouts and reproduces for one growing season before it dies. The tiny, green plants grow no more than 4 inches tall, and can only live in wet environments, often where groundwater seeps through rock.  You’ll never see a lone monkeyflower — the diminutive plants grow by the thousands in small, dense patches. Monkeyflower is an accurate but somewhat misleading term — individual plants almost never grow flowers. They reproduce asexually, meaning that, rather than containing a mix of genes from two parents, each individual is a genetic copy of a single parent. Looking closely at a reproductively active monkeyflower, you’ll see miniscule growths coming from its petioles (or leaf stems). These aren’t galls or some other plant infection — these are new monkeyflowers. Bulbils fall from their parent plant and grow into plants of their own. It’s similar to how some sea sponges and corals reproduce by budding; in fact, an alternate name for the species is the budding monkeyflower. Because they reproduce asexually, monkeyflowers exist in “clones,” populations of genetically identical individuals — all of the plants at Staunton, for example, are a single clone.

“It’s pretty bizarre, how it makes its way in the world,” said Mark, an expert on the species. There are other plants that reproduce asexually, including some other species of monkeyflower, but growing identical clones on the leaf stems seems to be unique to this species. “I don’t know of another plant that does this,” said Mark.

As we walked to our first stop Mark and Savanna mused on some of the “rules” of biology that the species breaks, and how some of the most basic methods of ecology are difficult to apply to it. For instance, when you find a patch of monkeyflowers, how do you count them? Do you count the number of fully grown plants or the bulbils on the plants? In sexually reproducing plants — sunflowers, for instance — the distinction between plant and seed is pretty clean, but in a plant that sprouts genetically identical growths that turn into new plants, the line is less clear. Mark said that when he started studying the monkeyflower in graduate school, “all of a sudden, what it means to be an individual got confusing. It depends on how you look at it.” 

Savanna used clonal reproduction of aspens, in which many individual trees are connected by a common root system, as an analogy. “If you have a whole stand of ten thousand, however many, hundreds of thousands of trees, is that one individual?”

Even the term “population” doesn’t quite suit the monkeyflower: In ecology, a population is defined as a group of breeding individuals, which doesn’t exactly apply to a species that doesn’t breed. 

Aside from the strange life of the monkeyflower, plant development in general can get pretty weird. Plants grow in ways that are more flexible and open-ended compared to animals. As we ducked under willow branches and scrambled between shrubs over the uneven forest floor on the more difficult stretch of our hike, we came across one such haywire example. It was a short, green plant with bayonet-like leaves along most of its stem except for the very top, where two leaves were joined at the tips, forming a halo around two or three other leaves, which were fused in an inelegant bunch. Savanna identified the plant as fireweed, a kind of willow herb, and noted the fasciation the plant had undergone. Fasciation describes abnormal development caused by disturbances to a plant’s growth, be it an infection or herbivores feeding on it. Sometimes, fasciation can be so extreme it makes a plant unrecognizable. “That makes the plant identification really hard sometimes,” said Savanna.

Our rough journey was leading to Staunton’s towering granite cliffs, where isolated patches of monkeyflowers are known to grow. Savanna and Mark scrambled up the cliffsides to check for plants — as montane botanists, it’s natural they’re both rock climbers. 

Along with plenty of moisture, shallow soil is a key ingredient to monkeyflower habitat. But why the plants prefer this is something of a mystery. It could be that monkeyflowers are habitat specialists, adapted to the particular chemistry of these thin layers of soil. Or it may be they just look like specialists — Mark and Savanna suspect that because monkeyflowers are bad competitors, they’re easily pushed out by other plants, so they only take hold in habitats where there isn’t much competition to begin with. “They’re kinda wimps,” Mark joked.

Because of their limited habitat options and sensitivity to competition, monkeyflowers have a delicate presence, and Savanna worries about potential threats to the species. “One of the seeps we went to a few weeks ago, there’s some weeds around there, and I definitely worry about that with Mimulus [the genus of the Rocky Mountain monkeyflower],” she said. “If there’s plants like cheatgrass that are coming in, sucking up all the moisture, then that might compete with the monkeyflower.”

It’s not just weeds that put the monkeyflower in a fragile position. Because they grow in small, dense patches, something as simple as a hiker stepping on them, a coyote lying down on them or a flash flood crashing through could wipe out an entire population. Water is a limiting factor in Colorado, leaving only a few places where monkeyflowers can sprout up. And their method of reproduction doesn’t exactly make them resilient to a changing landscape. In sexual reproduction, genes are reshuffled every time a sex cell is made. When two sex cells join to make an embryo, they form an individual with a unique combination of genes. In asexual reproduction, a parent produces offspring that are genetically identical to itself — there’s no reshuffling, no new gene combinations, no mix of traits in a population. This is one of the downsides of asexual reproduction. If there’s a radical change in an environment, a sexually reproducing population has genetic variety, and so it’s more likely that some individuals will have the right genes to survive that change; in an asexual population, all the eggs are in one basket (even though there are, literally, no eggs), and if none of the handful of genes in that population prove helpful in a changed environment, the decline can be rapid. “When you have all clones, they all have the same DNA,” said Savanna. “They’re susceptible to the same temperature fluctuations. … Asexual species are definitely thought to be more vulnerable to a changing climate. They can’t adapt as quickly. So that’s definitely a huge concern for this species.” 

CPW’s conservation efforts are designed with these vulnerabilities in mind. CPW-funded studies have increased monkeyflower populations, making the species more resilient to small, but destructive, events. In these studies, conducted in the 2010s, researchers introduced bulbils from greenhouse-grown monkeyflowers into promising new habitats. Many of these patches have persisted — sprouting up plants that produce a new, successful generation of bulbils, year after year — for nearly a decade. Staunton’s updated management plan protects monkeyflower areas by including them in protection zones where no new development will occur. CPW’s Rare Plant and Invertebrate Program also hopes to further conservation of the species by collecting bulbils from each clone to create a genetically representative captive population, which can be sourced from for restoration projects. Ongoing survey work monitors areas where plants are either thriving or have declined, and informs CPW’s efforts to protect, conserve and restore populations.

Journey to the center of Staunton

We climbed up to a small ledge under an overhang, where the cliffside recessed into a small, den-like shelter. A carpet of moss led into the shelter, creating a bed for a colony of little green plants with oval leaves: Rocky Mountain monkeyflowers.

To have come this far for such an unassuming plant could have seemed anti-climatic, but the simplicity of the monkeyflower was restful. There were no brilliant colors, no busy scenes of bees or butterflies bouncing between flowerheads, no powerful fragrances. All of that can be lovely, but the minimalism of the monkeyflower made it seem more exotic, a secret hidden in a remote jungle, an inconspicuous treasure that anyone could walk right past and never notice.

Mark guessed that there were 2,000 to 3,000 plants in this patch. The moss bedding wasn’t very damp, and there were some plants in the less shady area of the patch that had dried up. This patch would not likely produce many more bulbils for the season, but we were in time to see plants bearing “armpit babies,” as they’re sometimes referred to with a giggle.

“I wish some of these were flowering, but they’re not,” Mark said. “And they might later. … A lot of them just persist this way, and they’ll never flower. But some do.” 

The occasional flowering could solve a notorious Rocky Mountain monkeyflower mystery. Research at University of Northern Colorado found that the entire species consists of only 33 clones. Its genetic diversity is very low, but not as low as it could be. Individuals that flower could sexually reproduce with one another, providing the occasional opportunity to reshuffle the deck and introduce new genes to populations. 

Another mystery is the species’ range. Not so much what their range is, but how it got to be so surprisingly large.  “It’s kind of widespread for being such a small, patchy thing,” said Savanna. “It’s not just in Staunton State Park; there’s populations up in Rocky Mountain National Park all the way down to Deckers. … How do these bulbils get to these places?” 

Some plants disperse by being eaten by animals, but those typically have hard coatings that keep them from being digested, not like the soft, fleshy bulbils of the monkeyflower. A likely candidate is water currents carrying bulbils to other locations, but this doesn’t quite explain the extent of the species’ range. “I’ve got to think that dispersal is an extremely rare event, but maybe we’re missing something,” Mark wondered. 

Mark and Savanna continued to “geek out” on monkeyflower mysteries: Can bulbils survive through multiple winters before they root? Did its unique mode of reproduction evolve in only this species, or was it once more common, and this is the only species that remains? Is its range large but patchy because the bulbils travel by some unknown means, or is it that the species once had a more intact distribution, and what we have now are small relics of that population?

Though they seem to have strict habitat requirements, Mark pointed out that monkeyflowers do pop up in surprising places. “Many of them have thrived in places that have recently burned,” he said.

“Earlier, you called them wimps!” Savanna said. 

“Maybe they just live in little protected spots.”

“Maybe that doesn’t make them wimps; that makes them smart.”

Out of the weeds, and back in again

Once we had made our way out of the brush, with scratches and battle scars to prove it, we returned to a comfortable, even trail on our way back to the parking lot. With all of my technical questions out of the way, I was ready to end the day with a question that, if you’re ever at a party with a bunch of botanists, I recommend.

“Do plants have behavior?” I asked.

And off we went into a long conversation on what we mean by “behavior,” what it means to be conscious, panpsychism (look it up), the meaning of life and other things that have nothing to do with the conservation or management of the Rocky Mountain monkeyflower. But part of the reason we conserve rare species like this is because of the conversations they spark, what they tell us about life — and how they make nature worth exploring.

As for the question “Do plants have behavior?” I’ll leave that to botanists and panpsychists to answer. Not my circus, not my monkeyflowers. 

By: John Anglin, CPW Communications Specialist