The Monthly Orchid: What do you get when you cross a Coralroot & a wasp?

Answer: Capsules filled with seeds! (Striped Coralroot, Awinch1001)

Welcome back to the The Monthly Orchid, a series about South Dakota's native orchids. This month we again look at Coralroots, specifically the Striped Coralroot, Corallorhiza striata. Coralroots aren't particularly showy, but this one is a bit of an exception. Though the lip petal is small, its stripes are bold. Might they have a purpose? To this, Charles Darwin would reply with an emphatic "Yes!"

Corallorhiza striata; note yellow pollen positioned above base of lip (Freudenstein & Barrett 2026).

Darwin was fascinated by orchid flowers, largely because "the contrivances by which Orchids are fertilised are as varied and almost as perfect as any of the most beautiful adaptations in the animal kingdom." In this diversity, he saw an opportunity to respond to criticism of On the Origin of Species, which he published in 1859.

Just a few years later, Darwin finished another book—The Various Contrivances by which Orchids are Fertilised (1862). In the Introduction, he explained the purpose of his "little treatise" (c. 300 pages):

"Having been blamed for propounding [natural selection] without giving ample facts, for which I had not sufficient space in that work, I wish here to show that I have not spoken without having gone into details."

A myth Darwin intended to debunk was the notion that orchid beauty is "the result of the direct interposition of the Creator" for the pleasure of humans. Wrong! Beautiful orchid flowers are the result of natural selection, and like the vast majority of flowers, they have one purpose—continuation of the species, via sex. 

Why such varied and gorgeous lips? From Kunstformen der Natur, E. Haeckel, 1899.

In last month's post, a Coralroot seed encountered just the right underground fungus, germinated, started to grow, and emerged from the Underworld. We left it surviving on carbon captured by trees and shared (involuntarily) by the fungus. What next? At some point we should see buds, followed by flowers, and then capsules with seeds. Must the fungus help with all this as well? Aside from providing sustenance for growth, the answer is "No". In the case of the Striped Coralroot, however, dependency continues. Now another type of creature will be will be duped.

For most flowing plants (angiosperms), pollination is required to produce seeds. This is what drove evolution of the astonishing diversity in orchid flowers.

South Dakota orchids: Helleborine, Yellow Lady's Slipper, Prairie Fringed Orchid; note the varied contrivances.

With many examples (1), detailed descriptions and lengthy discussion, Darwin was able to argue convincingly that most orchids are designed with insects in mind.

"these contrivances have for their main object the fertilisation of the flowers with pollen brought by insects ... In almost all the species, one of the petals, which is the properly upper one, is larger than the others and stands on the lower side of the flower, where it offers a landing-place for insects, having been carried round by the twisting of the ovarium (2). It is called the lower lip or labellum, and often assumes most singular shapes." (italics mine)

In addition to specialized lips, orchids employ a variety of strategies to lure pollinators (Ackerman et al. 2023; Wikipedia). The most common is attraction by means of reward, e.g., nectar, oil, perfumes. These are given in exchange for pollen transport—arrival from or delivery to another orchid of the same kind. Flower shape, color pattern, and scent are commonly used to attract a specific pollinator, reducing the chance that pollen is wasted on the wrong orchid. 

But many orchids are not so nice. At least a third of the 30,000 known species rely on deception to attract pollinators. Having become highly specialized through natural selection, they are very good at this. Here are some examples.

• An orchid that provides no nourishment has flowers very similar to those of a plant that does. This is feeding deception, the most common type of deceptive pollination. 

• In brood-site deception, an orchid's flowers look like perfect egg-laying sites to the pollinator (see next photo). 

• Even more remarkable is pseudo-antagonism, in which a flower mimics an enemy of the pollinator, invoking an attack during which pollen is transferred!

Cypripedium lichiangense, the Lijiang Cypripedium (Steve Garvie). It offers an appealing (stinky!) but fake brood-site for Ferdinandea cuprea, a hoverfly (Ackerman 2023).

The most fascinating strategy (based on number of studies and websites) appears to be sexual deception, or pseudocopulation. It's the second most common type of deceptive pollination in orchids, documented in at least 22 genera (Ackerman 2023). Perhaps you have already guessed—Striped Coralroot is a sexually deceptive orchid! In fact, it's the first example of a pseudocopulatory orchid from North America!! (Freudenstein & Barrett 2026)

Corallorhiza striata, Andrey Zharkikh.

Freudenstein and Barrett used an insect net to capture wasps visiting Striped Coralroot flowers. They sexed them by looking for a prominent ovipositor. All 28 were male. Another 13 males were captured and sexed in photographs. The researchers then probed 30 of the flowers visited, and found no nectar. 

To determine what was attracting the wasps, they opened a plastic bag of Striped Coralroot flowers inside a net cone, hoping to release volatile scent compounds. Sure enough, within two minutes a swarm of 10 wasps appeared, flew around the cone, and landed on it (they couldn't get to the flowers).

And the stripes? The authors found no obvious resemblance between flowers and female wasps, but the "red stripe down the center [of the lip] flanked by two lighter patches could signal a wasp metasoma" (a body segment). I wonder—how might one test this hypothesis?

Whatever the attraction, all visiting wasps were the same kind—Pimpla pedalis, which is parasitic on the Pale-Winged Gray, a moth that defoliates Eastern Hemlock. In other words, the orchid dupes a wasp that is parasitic on the larvae of a moth that harms trees. Go Coralroot! (3)

If you are unable to view Pimpla pedalis "mating" with Corallorhiza striata (above), go to Freudenstein & Barrett 2026 (open access) and download the video in Supporting Information at the bottom of the page. Or try this video narrated by David Attenborough. It includes neither Striped Coralroot nor Pimpla pedalis, but is quite entertaining!

Now it's time to leave the Coralroots and move on to orchids with morals as well as beauty, perhaps Cypripedium (Lady's Slippers).

"As Orchids are universally acknowledged to rank amongst the most singular and most modified forms in the vegetable kingdom ... examination of their many beautiful contrivances will exalt the whole vegetable kingdom in most persons' estimation." (Darwin 1862, italics mine)

Cypripedium (Darwin 1862).

Notes

(1) Darwin's book includes exotic as well as British orchids. He received many specimens after reaching out to colleagues and collectors.

(2) Darwin is referring to resupination, which is common in orchid flowers. In bud, the lip petal is oriented upward, but by the time the flower opens, the ovary (sometimes the flower stalk) has twisted enough to orient the lip downward. See The Upside Down World of Orchids.

(3) In the orchid's ruse, Freudenstein and Barrett saw the opportunity for an especially alluring title: "Corallorhiza striata is the first example of a pseudocopulatory orchid in North America and an instance of 'double deception' in fully mycoheterotrophic plants." Wow, that's so cool! But wait ... is this really double deception? That depends on your opinion of Coralroots after reading last month's post.


Sources (in addition to links in post)

Ackerman, JD, et al. 2023. Beyond the various contrivances by which orchids are pollinated: global patterns in orchid pollination biology. Botanical Journal of the Linnean Society 202:295–324. https://doi.org/10.1093/botlinnean/boac082 

Britannica. Orchid/natural history/pollination. Accessed August 2026.

Darwin, Charles. 1862 (1904, 7th printing of 2nd edition). The Various Contrivances by Which Orchids Are Fertilised by Insects. London: J. Murray. https://doi.org/10.5962/bhl.title.84436

Freudenstein, JV, and Barrett, CF. 2026. Corallorhiza striata is the first example of a pseudocopulatory orchid in North America and an instance of“double deception” in fully mycoheterotrophic plants. American Journal of Botany 113(4): e70185. https://doi.org/10.1002/ajb2.70185

USDA Forest Service. Coralroot Orchids. The Celebrating Wildflowers—Beauty of It All website is a joy to wander through! I wish I knew whom to credit for it.

The Monthly Orchid: Coralroots—parasitic cheats or just slackers?

I walked right by these Coralroots! Fortunately I returned the same way and saw them.

Welcome to the The Monthly Orchid, a series of blog posts about South Dakota orchids. This one features Coralroots, genus Coralloriza—small inconspicuous plants but surprising or even shocking in their ways. After considering their manner of living, you can share your opinion of them in a Comment.

Five Coralroot species grow in South Dakota, all in the Black Hills. But the rest of the state is not nearly as well botanized as the Hills, and these little orchids may be lurking in shady hardwood forests far to the east. I wouldn't be surprised; four of our species occur nearby in Minnesota.

Coralroots are short, slender, drab, and easily overlooked. Stems come in a range of muted colors—red, brown, purple, yellow, occasionally greenish. Color can vary widely among populations of a single species, based on genetics and environmental factors, for example soil acidity.

Kneeling on the forest floor, we see a Coralroot's subtle beauty (Corallorhiza maculata).

Corallorhiza maculata, yellow population (USDA Forest Service).

Yellow Coralroots (Corallorhiza trifida) may be nearly green; but whether they can photosynthesize isn't clear (USDA Forest Service).

Like most orchids, a Coralroot begins life as a seed the size of a speck of dust, housed in a capsule with many thousands of its siblings. When the capsule dries and splits, the seeds are cast to the wind. Being so tiny, orchid seeds have NO endosperm—none of the nutritive tissue that most angiosperms (flowering plants) provide their embryos. So to germinate successfully, they must find help.

With luck, a Coralroot seed lands on a shady moist site with a network of fungal tissue (a mycelium) on or near the soil surface. If the fungus is the right kind—one that can form partnerships with plants (mycorrhizae)—there's a chance that germination will succeed.

Fungal mycelium—a network of hyphae that delivers water and nutrients to whatever is connected to it (Kirill Ignatyev).

When the seed germinates, the tiny embryo develops into a protocorm—a mass of cells less than a millimeter tall just beginning to differentiate. The basal cells allow a strand of fungal tissue to enter, but keep it from spreading further. This is the connection that will nourish the baby orchid. At this point, roots would begin to develop as well, but not in Coralroots. Instead, a short branched rhizome with rounded bumps begins to grow.

Rhizome of Corallorhiza (right) looks like coral, or did to Abraham Gagnebin, who named the genus in 1755 (USDA Forest Service).

Once above ground, most orchids start making their own food via photosynthesis, in tiny green solar-powered food factories in their leaves (and sometimes stems). But Coralroots have no leaves, only bladeless sheaths, and they are rarely green.

Corallorhiza innata (= C. trifida); note short branched rhizome and sheaths on stems (W. Muller 1904).

How do Coralroots survive without roots or leaves? For many years, they were thought to be saprophytic, decomposing and living off organic matter in the soil. Some reputable botany websites still describe them as such. But in fact, they cannot decompose organic matter. Instead, they're part of a complex drama, featuring three very different players.

Most orchids end their fungal dependency after germinating, but a young Coralroot can't. Without photosynthesis it needs a source of food, and will rely on the fungus for the rest of its life. But wait ... fungi don't photosynthesize either! This is where things get complicated.

Tripartate relationship: tiny orchids, fungal network, tree. Note that NO arrows come from the Coralroots.

If we search underground, just beneath the soil surface, we see that the fungal mycelium is linked not only to baby Coralroots, but also to tree roots, in a mutually beneficial relationship. A tree makes carbon compounds via photosynthesis and shares them with the fungus. In return, strands of fungal tissue increase the tree's uptake of water and minerals. Most importantly, the fungus fixes nitrogen in a form the tree can use.

However, while the trees and fungi are helping each other, the Coralroots continue to suck up nutritious carbon compounds from the fungal mycelium. From whence come such compounds? Might they come from dead organic matter decomposed by the fungus? Apparently not. Studies have shown that carbon delivered to the Coralroot by the fungus is produced by photosynthesis, not decay. Trees are the ultimate source.

Knowing this, what are we to think of Coralroots, those delicate little beauties of the forest? They live off carbon produced by trees and delivered by fungi, and contribute nothing in return ... NOTHING! Some botanists call them "heterotrophs" (consumers) that eat fungi. But "parasite" is more widely used and perhaps more accurate, given that they suck nutrients from fungal tissue. And yet no harm to the host has been shown. It's probably best to call Coralroots "mycoheterotrophs"—an awkward but nonjudgemental term specific to their tripartite relationships (Leake 1994).

USDA Forest Service.

What do you think of Coralroots? Do you forgive them their selfish ways? It's tempting to do so, but be aware—they have another dark side, and it has to do with sex! Stay tuned.

Sources (in addition to links in post)

Britannica's mycoheterotrophy article is detailed, interesting and clear. Here's their summary, my insertions in brackets:

"Mycoheterotrophs leach the carbohydrates that the fungi obtained from symbiotic plant partners [trees] and provide no reciprocal benefits. This interaction creates a tripartite relationship involving the autotrophic plant [tree], the fungus, and the mycoheterotrophic plant [Coralroot], with the mycoheterotroph serving as the ultimate sink for the carbon fixed by the autotrophic plant."

Leake, JR. 1994. Tansley Review No. 69. The biology of myco-heterotrophic ('saprophytic') plants. New Phytologist 127:171-216. Free access.

Leake, JR. 2005. Plants parasitic on fungi: unearthing the fungi in myco-heterotrophs and debunking the ‘saprophytic’ plant myth. Free access. 

USDA Forest Service. Celebrating Wildflowers: Coralroot Orchids. This is a wonderful website, offering so much for us to enjoy and learn! I wish I knew whom to credit. Accessed July 2026.

The Monthly Orchid—an introduction

The pouch-like lips of Fairy Slippers (Calypso bulbosa) are exquisite with their purple patterns and bright yellow hairs. No wonder fairies collect them at night to wear for dancing! (NPS)

Once again, I'm starting a series of posts about South Dakota plants—in part so that I can learn more about the state's flora (I'm still contributing to the online guide). In 2024 I wrote about trees, mostly the less familiar ones from the eastern part of the state. Last year I focused on ferns and fern relatives (lycophytes), and became a pteridomaniac in the process!

This year, after writing descriptions for sedges and rushes, and while starting on grasses, I considered doing a series about graminoids. But after a few weeks of struggling with species differentiated by tiny green structures, I came to my senses and went in a totally different direction—orchids! Their flowers are colorful, sweet-scented, diverse, relatively large, and highly-evolved.

Twenty-seven native orchid species have been reported from South Dakota. Some have large colorful flowers. Others have sweet-scented flowers, or flowers with unusual parts (e.g. threadlike or deeply dissected petals). But most of our species have flowers that aren't showy. They're small and subdued in color—white, greenish, yellowish, or brownish red. But up close they're gorgeous and obviously orchids.

Spotted Coralroot (Corallorhiza maculata); the white lip with purple spots has yellow gobs of pollen hanging over it; lip c. 6 mm long (MWI).

Like almost all orchids (99%), ours have a combination of features unique to the family: a LIP petal (tepal), a COLUMN consisting of the stamen(s) and pistil, POLLINIA made of pollen grains, and minute SEEDS.

Parts of an orchid flower (Serena Aceto).

The LIP or labellum is one of an orchid flower's six tepals (three sepals and three petals). Five of the tepals are more or less alike, but the lip is quite different—in shape, color, size and more. It's also distinctive among species, and is used in identification (fortunately it's easy to see). The lip appears to provide a landing platform for visitors, and species-specific forms are thought to be designed for specific pollinators—the product of coevolution.

Stream Orchid (Epipactis gigantea) has lips with "tongues"; these move when the flower is bumped, hence its other name: "Chatterbox"; flowers to c. 5 cm wide (Dcrjsr).

The lip of Loesel's Twayblade (Liparis loeselii) is showy relative to the other tepals, 2 of which are horizontal and threadlike; flowers to c. 1 cm long (MWI).

Most orchids have a single stamen, which is joined with the pistil to form a COLUMN. Among species, columns differ in size, shape, color and function. In White Lady's-slipper (below), the top of the column presses against the lip, preventing pollinators from leaving the way they came in. Instead they must exit via a narrow slit in the back of the pouch. Inexperienced bees may take up to 15 minutes to find the exit, and may fall prey to crab spiders lurking within! (source)

Small White Lady's-slipper (Cypripedium candidum) has a glossy white inflated lip to 2.5 cm long; yellow flap with red spots is the column tip (MWI).

In most orchids pollen grains are amassed into POLLINIA, bound together by threads of clear sticky viscin. Pollinia are carried off by pollinators to be deposited (hopefully) on stigmas of the same species. The advantages of dispersing pollinia rather than pollen grains will be explained shortly (below).

Ophrys orchid with a pollinator about to get hit with yellow pollinia (ErwinMeier; arrow added).

Finally, orchids produce the tiniest of SEEDS, which number in the thousands or even millions per flower! This means that there are equally numerous ovules in a single pistil. Now we see the advantage of pollinia. Thousands or sometimes millions of pollen grains packed into a pollinium land on a stigma all at once, ready to fertilize the multitude of waiting ovules.

Orchid seeds are very different in another way. Most flowering plants (angiosperms) have double fertilization, producing seeds with both an embryo and a stash of endosperm to feed the seedling as it starts its life. But not orchids. There is no double fertilization, and the tiny seed contains no endosperm to sustain the baby seedling. Even the embryo is much reduced—just a small mass of mostly undifferentiated cells.

Seed of Autumn Coralroot (Corallorhiza odontorhiza), 0.2 mm long! © Freudenstein 2024, CC BY-NC.

When an orchid's capsules dry and split, millions of dustlike seeds are cast to the wind, seemingly with little chance of survival. And yet orchids are said to be one of the most widespread families of flowering plants, both geographically and ecologically! (Brittanica) Seeds and their strategies are what fascinate me most about orchids, far more than the showy diverse flowers. But this introductory post has gone on long enough. So we will stop here, and let the mystery be for now.

"Orchideae" from Ernst Haeckel's Kunstformen der Natur (1899); see source page for names.

Sources (in addition to links in post)

Arditti, J, et al. 2025. Darwin’s prescient letter regarding orchid mycorrhiza. Lankesteriana 25: 83–102. http://dx.doi.org/10.15517/y157kw10 

Brittanica. Orchid. Accessed May 9, 2026.

Freudenstein, JV. 2025. Orchid phylogenetics and evolution: history, current status and prospects. Annals of Botany 135: 805–821. https://academic.oup.com/aob/article/135/5/805/7901162

Wikipedia. Orchids. Accessed May 9, 2026.

Monthly Fern Finale—Moonworts!

"A very singular and very pretty plant ... [leaflets] are rounded and hollowed, and thence its name came of Moonwort" Sir John Hill, 1770. (image from Atlas der Alenflora 1882).

About 2075 years ago, during the first century BCE, Roman philosopher Cicero wrote of introductions—their importance and how they should be constructed (1):

"one's opening remarks, though they should always be carefully framed and pointed and epigrammatic and suitably expressed, must at the same time be appropriate to the case in hand; for the opening passage contains the first impression ... and this ought to charm and attract the [reader] straight away."

After looking up "epigrammatic" (relating to a short saying or poem that expresses an idea in a clever, funny way), I sat down to construct an introduction "appropriate to the case in hand" — Moonworts.

First the epigram, from Botrychium lunaria by Giles Watson.

Hear the latch click in the gloom,

Thus gain admittance to the room.
By fern and stealth, no guile nor wealth
Can buy a lock to hinder me. 

Now the charm, of which there's no shortage!

After an unknown number of years underground, Botrychium simplex grows a leaf (J. Hollinger).

Moonworts (Botrychium species) are attractive little ferns, and it's unfortunate they're rarely seen. They live mostly underground in the intimate company of Glomus—a fungus that forms mutually beneficial subterranean relationships with nearly 80% of vascular plants. Typically Glomus supplies nutrients to the plant, and the plant supplies Glomus with carbohydrates via photosynthesis. But photosynthesis requires sunlight, so how can a Moonwort make carbohydrates if it lives underground? Maybe it's a parasite rather than a partner. This is just one of Moonworts' mysteries.

When conditions are right (another mystery), or perhaps when the stars align, a Moonwort sends up a single leaf. Though distinctive it's difficult to spot, being small, short-lived, and often hidden in vegetation or duff. But lucky is the finder of a Moonwort! If collected by the light of a full moon, the fertile part can be used to pick locks, unshoe horses, and turn mercury to silver.

Moonwort leaf with a sterile leaflike trophophore and a fertile (magical) sporophore; closeup shows sporangia have opened and released spores (Britton & Brown 1913).

Mingan's Moonwort releasing spores; soon it will wither and be gone (R&N Crawford).

The first known scientific description of Moonworts appeared in 1542, in a revolutionary herbal by physician and botanist Leonhart Fuchs: De Historia Stirpium Commentarii Insignes, Notable Commentaries on the History of Plants. It contained 500 high quality and largely accurate illustrations to help with identification—a novel approach which Fuchs felt obliged to explain: "a picture expresses things more surely and fixes them more deeply in the mind than the bare words of the text."

Lunaria minor, from Fuchs's 1542 herbal. BHL

Leonhart Fuchs c. 1543 (source).

Descriptions in Fuchs's herbal were brief and often "borrowed" from earlier works, an accepted practice. Lunaria minor was said to have a round stem, with a single leaf divided into seven parts and with a stem atop which were seeds (fern reproduction was assumed to involve seeds, though none had been found).

Lunaria minor (the name) and Moonwort seeds would persist for several centuries. Then in 1753, pioneering plant taxonomist Carl Linnaeus put Moonworts in the genus Osmunda (but he too referred to seeds; spores weren't accepted until the mid 1800s). In 1845, Czech botanist Carl Presl moved Moonworts to the genus Botrychium, where they mostly reside today (2), and recognized 17 species. But in the first "modern" treatment of Moonworts, Jens Clausen (1938) reduced this to just six, all of which occurred in both Europe and North America.

We look back on Clausen's classification as much too simplistic. But nearly 50 years would pass before someone took enough interest in North American Moonworts to do something about it—specifically Warren and Florence Wagner, who upped the number to 22. Study and discovery have accelerated since. Currently 38 Moonworts are known for North America (Farrar 2024), with several more species in the pipeline.

A recently-described North American Moonwort—Botrychium farrarii (Legler & Popovich 2024). Note variation.

With so many species and such small plants, Moonwort identification is notoriously difficult (3). Characters often are minute (10x magnification helpful). Differences can be subtle, relative, and variable. No wonder we're regularly referred to experts for confident id. And the experts may resort to molecular techniques (e.g. DNA, enzymes) for verification.

So what are we to do in our South Dakota plant guide, aimed at enthusiasts as well as professionals? We shall follow the advice of Leonhart Fuchs, still sound after all these years. High quality photos will accompany relatively brief descriptions. Discussion of lookalikes will note similar species, offer possibly useful differences, and most likely refer the user to technical manuals and experts.

Fortunately, we do NOT have to identify a Moonwort to species to enjoy it! Just finding one is exciting, and examining it closely can be magical. For example ...

Botrychium matricariifolium was named for its twice-divided trophophores, reminiscent of the leaves of matricary (chamomile). It appears to be rare in South Dakota, found at a few sites in the Black Hills.

Matricary Moonwort is a relatively large moonwort—to 25 cm tall (MWI).

Up close, the trophophore has a lacy elegance (MWI). 

The branched sporophore has many bead-like sporangia, each one containing thousands of spores! (MWI)

Prairie Moonwort, Botrychium campestre, may be our smallest Moonwort. In South Dakota it occurs in grasslands, true to its name. It too appears to be rare, but one never knows with Moonworts! It may be hiding in the grass, or lurking underground for years, waiting for the stars to align.

Prairie Moonwort usually is less than 4 cm tall (NPS).

Botrychium simplex, Least Moonwort, has been found at widely scattered sites, from grasslands and sandhills in eastern South Dakota to a picnic area in the Black Hills. It's both extremely variable and quite similar to at least four other species in the state, making id extra difficult.

Variation in Botrychium simplex—yikes! (compiled from this source).

I'm including the next photo because I loved the comment on the field form—"Not expected out here!" That's a Moonwort for you. They seem to do just fine beyond the limits of "typical habitat". But typical habitat may just be where we typically look for them. Obviously we still have a lot to learn!

Least Moonwort (center) along a seepy creek in sagebrush steppe in Nevada! (mreala)

And so the Monthly Fern series comes to a close. Thank you for reading, happy holidays to all, and best wishes in the year to come!

Notes

(1) In De Oratore, Cicero was actually addressing speaking, but his advice for introductions seems applicable to writing.

(2) Some former Botrychium species are now in separate genera, though not everyone agrees. In South Dakota we have Botrypus virginianus (Rattlesnake Fern) and Sceptridium multifidum (Leathery Grapefern).

(3) In contrast to seed plants and true ferns, where identification relies heavily on reproductive parts (flowers, cones, spore-filled sporangia), Moonwort identification relies almost entirely on the leaf-like trophophore. What it's shape and size? Is it divided? how many times? For leaflets—specifically the lowest pair—determine shape, margins, and how they attach to the midrib. Compare them to those above ... and more.  Small size and variability compound the challenge.

Sources

Farrar, DR, and others? Moonwort Systematics, Ada Hayden Herbarium, Iowa State University. Accessed December 2025. A great resource, with descriptions and photos for many Botrychium species.

Farrar, DR, Gilman, AV, and Moran, RC. 2017. Ophioglossales, in New Manual of Vascular Plants of Northeastern United States and Adjacent Canada. NYBG Press (apparently not yet published—another moonwort mystery).

Farrar, DR, and Johnson, C. 2024. Botrychium subgenus Botrychium: Moonwort biology basics. American Fern Journal 114:10-21. https://doi.org/10.1640/0002-8444-114.1.10

Hill, J. 1770. The useful family herbal: or, An account of all those English plants, which are remarkable for their virtues ...  BHL

Legler, BS, and Popovich, SJ. 2024. Botrychium farrarii (Ophioglossaceae), a new diploid Moonwort species from the Bighorn Mountains of Wyoming, U.S.A. American Fern Journal 114:32–48. PDF

A Darkling Path through the Ferny Ferns

Be there dragons here?

It's November and The Monthly Fern series is winding down. Looking back, I realized that most of the ferns I chose are distinctive—they're aquatic or have dimorphic leaves or are primitive lycophytes or grow large enough to inveil a romantic tryst! So this month's post will feature the ferny ferns (my term)—the ones we immediately recognize as ferns. However, figuring out which specific kind isn't guaranteed. If only ferns had flowers—so showy and diverse! Instead we must rely on leaves (1).

As the days shorten it would seem that writing descriptions for our Guide to South Dakota Plants would be appealing, especially given my current subjects—ferns and their relatives. But they can be difficult, and at times inscrutable. Of course they aren't the ones to blame. We are—specifically we botanists who seek order in their labyrinthine world.

I try to make my plant descriptions user-friendly, as our intended audience is broad—professionals, academics, students, enthusiasts, and eager novices (2). Being online makes this much easier. There will be many photos so I can shorten the text and minimize technical terms. Even so, there remain features that must be explained, for example the lovely lacy leaves of the ferny ferns.

The much-divided leaves of ferny ferns are the basis for "fernlike"—for example, "Western Yarrow leaves are fernlike" (SAplants).

Fern descriptions typically start with the plant—height, form (erect, spreading, sprawling), behavior (colony-forming, clumped), and other fairly straight-forward things. Leaves are next. Position (basal, on the stem), color, dimensions, and overall shape are easy to describe. But then ... we're faced with the dreaded degree of dissection. How many times is the leaf divided? Are there true segments? Are the segments themselves divided and are these divided as well? Here the guides I've been using as examples diverge, perhaps out of confusion. Suddenly the way forward becomes unclear; the path darkens considerably.

Entering the darkling world of leaf division.

"Leaf Division" from Fern Structure (USDA Forest Service).

In my web wanderings, I found a figure showing degrees of leaf division (above). It seems clear, though one needs to know that "pinnate" means divided and "-fid" means "nearly". For example, "pinnatifid" means nearly once-divided—division doesn't quite reach the midrib of the leaf as it does in "pinnate".

I intend to use this figure, perhaps as a pop-up, but will replace "pinnate" with "division" thereby eliminating the need for translation. "fid" situations will be accommodated with "nearly", for example "nearly twice-divided".

My version—actually a common approach, not my invention. 

Declaration of degree of division is followed by description of the ultimate segments—their shape, size, hairiness, margins, and such. This can provide much-welcomed help with identification. 

Ready for a test? Using the photos below, describe leaf division in Male Fern, Dryopteris filix-mas, and characterize the ultimate segments.

Male Fern's clumped ascending leaves can be more than a meter long. Аимаина хикари

Once-, nearly twice-, or twice-divided? Note the toothed (but not spiny) margins of the ultimate segments (click on image to view). Nick Turland

The sources I use all say that leaves of Male Fern are nearly twice-divided (pinnate-pinnatifid). But you needn't feel bad if you chose a different answer—you are correct. Male Fern leaves are usually once-divided at the tip, often twice-divided near the base, and nearly twice-divided in between. But adjacent segments can differ as the photo shows. Some are true segments, with division reaching all the way to the midrib. Others don't quite make it.

With no obvious path through this shadowy world, let's change the subject.

It's not uncommon for fern identification to be difficult, as even experts acknowledge (e.g., Cobb et al. 2005):

"Many ferns are distinguished by the finer details of the blade and how it is divided, and descriptions of fern blades can seem difficult and frustrating to beginners" (italics mine; I too get frustrated, and take offense at being labeled a beginner).

This is where a truly user-friendly guide can help, with lookalikes and tips for identification.

Be discriminating in your choice of guides.

In South Dakota we have an especially fine (= difficult) example of lookalikes—Fragile Fern vs. Oregon Cliff Fern. They grow on the same types of sites and look oh-so-similar. Both have nearly twice-divided leaves (often twice-divided at the base) and their ultimate segments have rounded tips and toothed margins.

Fragile Fern, Cystopteris fragilis (MWI).

Oregon Cliff Fern, Woodsia oregana (MWI).

Several small but distinctive features can help with identification (10x magnification recommended). Ultimate segments of Fragile Fern are not glandular and usually hairless, and the margins are irregularly toothed. In contrast, Oregon Cliff Fern segments are glandular hairy (more so on the underside), and the margins are regularly toothed.

Fragile Fern, with irregularly toothed segments (MWI).

In Oregon Cliff Fern, segments are regularly toothed (MWI).

Those familiar with these ferns in the wild have another tip, and it's something that's easier to see. Our Cliff Ferns (Woodsia species) often have persistent dead leaf stalks. This isn't the case for Fragile Fern.

It's not unusual for a mature Cliff Fern to have more dead stalks than leaves (Andre Zharkikh).

You can relax now. No more tests. We're very close to the end, with reassuring light visible ahead. And if you found leaf division tedious and difficult, think how I must feel after attempting to explain it! Sometimes I have to remind myself that I love plants.

Notes

(1) Replacing fern terminology—frond, stipe, pinnae, e.g.—with the more familiar terms used for angiosperms—leaf, leaf stalk, leaflet—has become fairly common (for example, Flora of North America). Others adhere to tradition, explaining terms in a glossary or introduction (for example, Cobb et al. 2005).

(2) I'm not enough of an expert to write descriptions of South Dakota plants myself. Instead I rely on the knowledge of others, both in printed manuals and online. The majority of photos also are by others, available online through Creative Commons licenses.

(3) Some readers may be thinking, "Just find fertile leaves with sori!" (spore clusters). After all, we've been told repeatedly that sori are distinctive. But those of Fragile Fern and Oregon Cliff Fern are hard to distinguish at maturity. Fragile Fern does have distinctive pocket-like indusia, but only when young (see photo of leaf segments in post).

Sources

All fern art created with NightCafe AI Art Generator.

Cobb, B, et al. 2005. Peterson Field Guide to Ferns, 2nd Ed. Northeastern and Central North America. Provides excellent lookalike information and tips.

Minnesota Wildflowers, a guide to the flora of Minnesota. This was the first online guide I found, and remains the most user-friendly of those I've seen (there aren't all that many, online guides being relatively new). Fortunately South Dakota and Minnesota share many plant species, and this website will be our main source of photos.

USDA Forest Service. Ferns. Highly recommended.