Click here to return to the Botany Textbook table of contents.

Chapter 23: Living Without Plumbing: Mosses and the Nonvascular Plants

No flowers. No fruits. No seeds. No cones. And no vascular system. No xylem highways. No phloem delivery trucks. No internal plumbing of any kind.

These are the bryophytes (BRY-oh-fites), and they include three groups: mosses, liverworts, and hornworts. They’re the smallest, simplest, and most overlooked plants on the planet. Most people walk right over them without a second glance. Some people aren’t even sure they count as plants. (They do.)

And yet, bryophytes are quietly doing things that would genuinely shock you if you knew about them. They colonize bare rock. They survive in Antarctica. They can dry out completely, sit there looking dead for months or even years, and then spring back to life the moment water touches them. Some mosses carpet entire forests. Others glow in the dark. One genus has been used by humans for thousands of years as bandages, diapers, and insulation. A single genus of moss, Sphagnum, stores more carbon than all the world’s tropical rainforests combined.

For something you can squish between your fingers, that’s a pretty impressive resume.

So why are bryophytes so small? Why do they hug the ground instead of reaching for the sky like an oak tree or a redwood? And how do they survive without the internal plumbing that every other plant group in this book relies on?

The answer to all three questions is the same thing: they don’t have vascular tissue. And understanding what that means, and what it doesn’t mean, is the key to understanding everything about these plants.

Let’s start there.

What “Nonvascular” Actually Means

You know this word by now. We’ve been building toward it for chapters.

Way back in Chapter 5, we spent a lot of time getting to know the two tissues that make up a plant’s internal plumbing system. Xylem, the one-way water highway that pulls water and minerals up from the roots. Phloem, the food delivery network that ships sugars from the leaves to wherever the plant needs them. Together, those two tissues form the vascular system, and we compared them to pipes, highways, and plumbing so many times that the analogy is probably permanently stuck in your brain.

Every plant group we’ve studied so far has that system. Angiosperms have it. Gymnosperms have it. Ferns, horsetails, and club mosses have it. Even whisk ferns, those weird branching green sticks from Chapter 22 that barely have leaves, still have xylem and phloem.

Bryophytes don’t.

They have no xylem. They have no phloem. They have no specialized internal tubes for moving water or food from one part of the plant to another. Water that lands on a moss doesn’t get pulled up through an internal pipeline. It soaks in through the surface, cell by cell, the way a paper towel absorbs a spill. Slowly. Passively. With no pressure system driving it.

This is a big deal, and it explains almost everything about how bryophytes look and where they live.

Why No Plumbing Means No Height

Think about what xylem does in a tree. It doesn’t just move water. It provides structural support. Remember from Chapter 5 how xylem cells have those thick, reinforced walls? Those walls are strong enough to hold up a 380-foot coast redwood. Xylem is both the water pipe and the skeleton. The plumbing is the support system.

Bryophytes don’t have that. Without xylem, they have no internal scaffolding. No reinforced cell walls holding them upright. No rigid framework to build on. Trying to grow tall without xylem would be like trying to build a skyscraper out of wet paper towels. You might get a few inches off the ground before the whole thing flops over.

And that’s almost exactly what happens. Most mosses top out at one to four inches tall. A few unusually ambitious species can reach about eight inches in very wet, sheltered environments. The tallest moss in the world, Dawsonia superba from New Zealand and Australia, can reach about 20 inches, but that’s the absolute record, and it grows in consistently wet rainforest conditions where water is never a limiting factor.

Compare that to a coast redwood at 380 feet. The difference between the tallest moss and the tallest tree is like the difference between a paper clip standing on end and the Statue of Liberty. Same kingdom. Wildly different engineering.

Why No Plumbing Means Staying Wet

Here’s the other problem. Without a vascular system to pull water up from the soil and distribute it internally, bryophytes are completely dependent on their external environment for moisture. They absorb water directly through their surfaces, like a sponge, and they lose it the same way. When the air is humid and rain is frequent, they’re fine. When things dry out, they dry out too.

This is why you almost always find mosses in damp, shady places. The north side of a tree trunk. A rock beside a stream. The floor of a dense forest where the canopy blocks the wind and holds in moisture. The shady side of a building where the sun never quite reaches. Bryophytes aren’t in those spots by accident. They’re there because those are the places where water sticks around long enough for them to function.

But here’s something important: “dependent on moisture” does not mean “instantly dies without it.” Many bryophytes are incredibly tough. Some mosses can lose almost all of their internal water, shrivel up into dry, crunchy, apparently dead little husks, and then fully rehydrate and resume photosynthesis within minutes of getting wet again. This ability is called desiccation (DES-ih-KAY-shun) tolerance, and it’s something very few vascular plants can do. Most flowering plants will die if they lose even 30 to 40 percent of their water content. Some mosses can lose over 95 percent and bounce right back.

So bryophytes aren’t fragile. They’re just small. And wet. And honestly? Being small and wet turns out to be a perfectly fine strategy for conquering the planet, as long as you’re not picky about being noticed.

No Roots, No Problem (Well, Sort Of)

Here’s another thing bryophytes are missing: true roots.

Go back to Chapters 6 and 7 for a second. Remember all those root structures we studied? The root cap bulldozing through soil. The root hairs increasing surface area for water absorption. The vascular cylinder at the center with its star-shaped xylem core. The endodermis acting like a security checkpoint. All of that complex internal architecture exists because roots need to absorb water and minerals from the soil and then pump them upward through the vascular system to the rest of the plant.

Bryophytes don’t have a vascular system to pump things into. So they don’t need that kind of root. Instead, they have rhizoids (RY-zoyds), which are thin, hair-like filaments that grow out of the bottom of the plant and anchor it to whatever surface it’s growing on. Soil, rock, bark, concrete, basically anything that stays still long enough.

Here’s the key difference: true roots actively absorb water and minerals through root hairs, pull them into the vascular cylinder, and send them up through xylem. That’s a sophisticated, multi-step, actively managed process. Rhizoids don’t do that. They mostly just hold the plant in place. Some rhizoids can absorb a small amount of water, but they’re not running an absorption operation the way real root hairs do. They’re anchors, not pumps.

It’s like the difference between a boat’s anchor and a boat’s engine. The anchor keeps you in one spot. The engine actually moves you somewhere. Rhizoids are the anchor. Vascular roots are the engine.

The Three Bryophyte Groups

There are roughly 20,000 species of bryophytes alive today, and they fall into three groups. One of them is huge and everywhere. The other two are smaller and stranger. (Sound familiar? That’s basically the same pattern we saw with gymnosperms in Chapter 21 and seedless vascular plants in Chapter 22. Botany loves this pattern.)

Mosses: The Stars of the Show

Despite their tiny size, mosses are proper plants. They have stems, leaves, and chloroplasts, and they do photosynthesis just like every other plant we’ve studied. In fact, remember that photo of chloroplasts inside cells back in Chapter 12 when we were learning about photosynthesis? That was actually a moss leaf. Mosses are legitimate food-making, oxygen-producing, photosynthesizing plants. They’re just really, really small ones.

Now, botanists do like to point out that moss stems and leaves aren’t quite the same as the stems and leaves of vascular plants. Moss stems are sometimes called caulidia (kaw-LID-ee-uh), and moss leaves are sometimes called phyllidia (fill-ID-ee-uh). The reason for the different names is that moss leaves lack veins and don’t have the complex internal layers we studied back in Chapter 10. They’re simpler structures. But they do the same basic jobs: the stems hold the plant upright, and the leaves catch sunlight for photosynthesis.

Most moss leaves are only one cell thick. One. Single. Cell. Go back and think about the cross-section of a flowering plant leaf from Chapter 10, with its upper epidermis, palisade mesophyll packed with chloroplasts, spongy mesophyll full of air spaces, lower epidermis studded with stomata, and veins running through everything. That’s a whole multi-layered sandwich of specialized tissues. Here’s a diagram for review:

A moss leaf is a single layer of cells. No palisade layer. No spongy layer. No veins. No mesophyll at all. Just one transparent sheet of green cells, thin enough that light passes right through it. It’s about as simple as a leaf can possibly be and still work.

And it does work. Simple doesn’t mean broken. It just means efficient.

Liverworts: The Flat Ones

Liverworts are the second group of bryophytes, with roughly 7,000 to 9,000 species. The name sounds weird, and the origin is even weirder. In medieval Europe, people believed that a plant’s shape indicated what it was useful for treating. Some liverworts have flat, lobed bodies that looked, to medieval eyes, like a human liver. So, people assumed these plants must be good for treating liver diseases. They called them “liverworts” because wyrt is an old English word meaning “plant” or “herb.”

Did liverworts actually cure liver problems? No. Not even a little. But the name stuck, and here we are, hundreds of years later, still calling them liverworts.

Liverworts come in two basic forms. Thallose liverworts have flat, ribbon-like bodies that lie flat against the ground and branch as they grow, looking like green, rubbery straps. They don’t have obvious stems or leaves at all. The whole plant body is one flat sheet of tissue called a thallus. If you’ve ever seen something that looks like a little green pancake growing on wet soil or a damp rock, that was probably a thallose liverwort.

Leafy liverworts look more like tiny mosses. They have a stem-like structure with rows of small, leaf-like structures arranged along it. They can be hard to tell apart from actual mosses at first glance, but there are differences. Leafy liverwort “leaves” are usually arranged in two or three rows along the stem (mosses typically have leaves spiraling around the stem in more than three rows). Liverwort leaves also tend to lack the midrib (central thickening) that many moss leaves have.

Here’s something cool about liverworts: many thallose liverworts have special cup-shaped structures on their upper surface called gemmae (JEM-ee) cups. Inside these cups are tiny green discs called gemmae (singular: gemma). When a raindrop lands in the cup, the splash launches the gemmae out like tiny green frisbees. Each gemma can land nearby, attach to a surface, and grow into a brand new liverwort plant. It’s asexual reproduction powered by rain splash. The plant is literally using raindrops as a catapult system to clone itself.

Remember vegetative reproduction from Chapter 9, where we learned about all the ways plants can clone themselves with stolons, rhizomes, tubers, and bulbs? Gemmae cups are the bryophyte version of that same idea: making new individuals without seeds, spores, or sexual reproduction. Just pop out a clone and let the rain do the delivery.

Hornworts: The Weird Ones

Hornworts are the smallest and strangest of the three bryophyte groups, with only about 200 to 300 species. They get their name from their sporophytes, which look like little green horns or needles poking up from the surface of the plant. If you saw a hornwort, you’d probably think it was a thallose liverwort at first, because the main plant body is a flat, green thallus that sits on the ground. But those distinctive horn-shaped sporophytes sticking up from the surface give hornworts away.

Hornworts have a couple of features that make them genuinely unusual, even by bryophyte standards.

First, each cell of a hornwort typically has only one large chloroplast. Go back to Chapter 3 for a second. In most plant cells, there are dozens of chloroplasts floating around in the cytoplasm. A single mesophyll cell in a flowering plant leaf can contain 30 to 50 chloroplasts. Hornwort cells? Usually just one. One big chloroplast per cell. This is unusual among land plants and makes hornworts look a lot more like certain types of algae under the microscope.

Second, that spore-making stalk on a hornwort has a trick that neither mosses nor liverworts can pull off: it keeps growing from the base.

In mosses and liverworts, the stalk grows, the capsule opens, the spores fly out, and that’s it. Done. The whole structure is finished.

Hornworts don’t quit like that. The bottom of their stalk keeps producing new spore-making tissue while the top is already opening up and releasing spores. Picture a candle that keeps growing taller from the bottom at the same rate it melts from the top. Or a tube of toothpaste that refills itself from the bottom while you squeeze from the top. The horn just keeps going, ripening from the tip downward and sending out spores for weeks or even months.

That’s a pretty nice deal for a tiny plant. Instead of one quick burst of spores and done, a single hornwort gets to keep spreading its offspring over a much longer stretch of time.

The Life Cycle: Gametophyte Takes the Stage

Note: There is a lot of technical stuff in this section of the chapter. You don’t need to memorize it or even remember most of it. Just read through it and don’t panic if it doesn’t all stick!

Okay. Remember back in Chapter 22 when we learned that ferns have two stages in their life cycle? Let’s do a quick refresher, because mosses have the same two-stage system, but with a major twist.

Here’s what we learned with ferns. The big, leafy fern plant you actually see in the forest is the stage that makes spores. It’s called the sporophyte. When those spores land on wet soil, they grow into a completely different-looking plant: that tiny heart-shaped thing sitting on the ground that you’d barely notice without a magnifying glass. That tiny stage is the one that makes eggs and sperm. It’s called the gametophyte. The sperm swims to the egg, fertilization happens, and a new big leafy fern grows. Round and round it goes, alternating between the two stages.

With ferns, the big plant you notice is the spore-making stage, and the tiny thing you’d never spot is the egg-and-sperm stage.

Mosses do the whole thing backwards.

That soft, green moss you see growing on a rock or a log? That’s the egg-and-sperm stage. That’s the gametophyte (guh-MEE-toh-fyte). It’s the part that photosynthesizes, the part that lives for years, the part you actually notice when you walk through the woods.

So where’s the spore-making stage? It’s that little stalk with a capsule on top that you sometimes see poking up out of a moss cushion, like a tiny matchstick standing in a green carpet. That’s the sporophyte. And unlike fern sporophytes, which are big and independent, moss sporophytes are small, short-lived, and completely dependent on the green moss below them for food and water. They stay physically attached and never leave home. Think of a teenager who has a job (making spores) but still lives in their parents’ house and eats all their food.

This is the opposite of every other plant group we’ve covered in this book. In flowering plants, conifers, and ferns, the big plant you see is always the spore-making stage. In mosses, the big plant you see is the egg-and-sperm stage, and the spore-maker is just a tiny little stalk hitching a ride on top.

Let’s walk through the moss life cycle step by step.

Step 1: The Gametophyte Grows Up

A moss spore lands on moist ground and germinates. But it doesn’t immediately grow into a moss plant. First, it produces a thread-like network of green filaments called a protonema (proh-toh-NEE-muh) -plural: protonemata. The protonema looks a lot like a tangled web of green thread spread across the soil surface. It’s basically a flat, branching network of cells that photosynthesizes and gathers nutrients.

After the protonema establishes itself, buds form along its surface, and those buds grow upward into the leafy moss shoots you recognize. Each leafy shoot is called a gametophore (guh-MEE-toh-for), meaning “gamete bearer,” because this is the structure that will eventually produce the reproductive organs.

A gamete is a reproductive cell, and there are two kinds: eggs and sperm. So, both the egg and the sperm are gametes.

So, the full sequence is: spore grows into protonema (thread stage), protonema buds produce gametophores (leafy stage), and the gametophores are what you see when you look at a patch of moss.

Step 2: Making Eggs and Sperm

At the tips of the gametophores, the moss produces reproductive structures. Just like ferns, mosses use archegonia to produce eggs and antheridia to produce sperm. These are the same structures we met in Chapter 22 during the fern life cycle, and they work essentially the same way.

Some moss species produce both archegonia and antheridia on the same plant. Others produce them on separate male and female plants. Either way, the setup is the same: an archegonium holds a single egg inside a flask-shaped chamber, and an antheridium produces many tiny, flagellated (which means they have little tails) sperm cells.

Step 3: Swimming (Again)

Here’s the part that should sound very familiar. The sperm need water to reach the egg. Just like fern sperm, moss sperm have two whip-like tails (flagella) that let them swim through thin films of water. A raindrop, morning dew, a splash from a passing animal, anything that creates a wet connection between the male and female structures will do. The sperm swim through this water to the archegonium and fertilize the egg.

This is why bryophytes need moisture to reproduce. Not just to stay hydrated, but because their sperm literally have to swim. No water? No fertilization. No fertilization? No sporophyte. It’s the same requirement we saw in ferns, and it’s one of the reasons bryophytes tend to live in damp environments.

Step 4: The Sporophyte Grows

In many mosses, the capsule has a ring of tiny, tooth-like structures around its opening called the peristome.

These peristome teeth respond to moisture in the air, just like the elaters on horsetail spores from Chapter 22. When the air is damp, the teeth curl inward and seal the opening, keeping the spores trapped inside. When the air dries out, the teeth flex outward and the opening spreads wide, letting spores drift away on the breeze.

Think about why this is so clever. Wet spores clump together and don’t travel well. Dry spores are light, separate, and catch the wind easily. So the capsule basically checks the weather before opening the door. Dry and breezy? Release the spores. Rainy and still? Keep them sealed up and wait for better conditions.

And here’s the wild part: there’s no brain making this decision. No sensors. No electronics. The whole system is built entirely out of dead cell walls that physically change shape when humidity changes. It’s an automatic, weather-responsive launch system, and it runs on nothing but physics.

Step 5: Start Over

The spores land somewhere, germinate into protonemata, grow into gametophores, produce eggs and sperm, and the whole cycle begins again.

Why Does This Matter?

This flipped life cycle is actually the key to understanding why mosses are the way they are.

In a flowering plant, the big plant you see has all the fancy equipment: xylem and phloem for transport, roots with complex plumbing, leaves with multiple layers. The egg-and-sperm stage is microscopic and hidden. It barely has to do anything.

Mosses are the opposite. The green moss plant is the egg-and-sperm stage, and it has to do everything: photosynthesis, absorbing water, anchoring to the ground. And it has to pull all of that off without xylem, without phloem, and without true roots. Meanwhile, the spore-making stalk just sits on top with one job: make spores. That’s it. It doesn’t even feed itself.

There are around 12,000 species of moss, but if you only remember one genus from this chapter, make it Sphagnum (SFAG-num). This one group of mosses covers enormous stretches of the Earth’s surface, stores mind-boggling amounts of carbon as discussed earlier, and has shaped entire landscapes. It’s also been used as everything from wound dressings to baby diapers. Not bad for a plant with no roots.

Sphagnum’s Water Trick

Sphagnum has an almost absurd ability to absorb and hold water. A single clump of Sphagnum can hold 15 to 25 times its dry weight in water. Some species can hold even more. For comparison, a typical kitchen sponge holds about 10 to 15 times its dry weight. Sphagnum out-sponges a sponge.

How? The secret is in the leaf structure. Sphagnum leaves have two types of cells arranged in an alternating pattern. Small, narrow, green cells do the photosynthesizing. Surrounding those green cells are large, hollow, dead cells with reinforced walls and big pores in them. These dead cells are basically built-in water tanks. They’re empty husks with holes in them that fill with water through capillary action and hold it like tiny reservoirs.

It’s like building a wall out of bricks and water balloons in an alternating pattern. The bricks do the structural work and the water balloons hold the water. Except in Sphagnum, the “water balloons” are dead cells specifically shaped for maximum water storage.

This water-holding ability is why Sphagnum was historically used in all sorts of practical applications. During World War I, Sphagnum moss was widely used as wound dressings for injured soldiers. It absorbs liquid better than cotton (twice as much!) and has mild antiseptic properties (the acidic environment it creates inhibits bacterial growth). Before the era of disposable diapers, some cultures used dried Sphagnum as diaper material for babies for the same reason. Native peoples in northern climates used it as insulation in clothing and shelters.

Also, in some parts of the world, people once heated their homes with fuel made partly from Sphagnum mosses. In bogs and wetlands, layers of dead sphagnum moss and other plants slowly built up over many years, forming a thick material called peat (as described earlier in the chapter). People cut the peat into brick-like blocks, dried them in the sun, and burned them for heat and cooking. Peat fires give off a distinctive smoky smell and were especially common in places such as Ireland and Scotland, where large peat bogs were plentiful.

Note to creationists: This video says mosses are one of the oldest plants. Many Christians believe mosses were just created at the same time with all the other plants.

Ecological Importance: Small Plants, Massive Impact

It’s easy to look at bryophytes and think, “Okay, they’re interesting, but they’re so tiny. How much can they really matter?”

A lot. It turns out they matter a lot.

Pioneer Colonizers

Bryophytes are often the first plants to show up on bare surfaces. A freshly exposed rock face, a patch of soil after a landslide, a burned area after a wildfire, a crumbling brick wall. These are places where most plants can’t get a foothold. There’s no soil, or not enough of it. There’s nothing to anchor roots into. There’s nothing to hold water.

Mosses don’t care. Remember, they don’t have true roots that need soil. Their rhizoids can grip bare rock. They absorb water directly from rain and humidity. They make their own food through photosynthesis. They need almost nothing to get started.

Once they establish themselves, they start building the foundation for everything that comes after. Moss cushions trap dust, dirt, and tiny particles from the air. Dead moss tissue accumulates and begins to decompose, forming a thin layer of primitive soil. That soil holds moisture and nutrients, and eventually, other plants (grasses, ferns, small flowering plants) can take root in it. Those plants add more organic matter as they grow and die, building the soil further. Over time, what started as bare rock with a smear of moss becomes a patch of soil thick enough to support trees.

This process is called primary succession, and mosses are often the organisms that kick it off. They’re the pioneers, the first wave, the advance team that makes it possible for everyone else to show up later. Without them, bare rock would stay bare rock for a lot longer.

Erosion Control and Water Regulation

Moss carpets work like living sponges spread across the ground. In forests, thick layers of moss soak up rainfall, slow down runoff, and release water gradually over time. Without them, rain hits bare ground, runs off fast, and carries soil with it. With a moss carpet in place, the water gets absorbed, held, and released slowly, which keeps streams flowing steadily instead of swinging between floods and dry trickles. In many northern forests, the moss layer on the ground is actually thicker than the soil underneath it. The moss isn’t just sitting on the landscape. In some places, it basically is the landscape.

Habitat for Tiny Creatures

If you’re small enough, a clump of moss is an entire world. Hundreds of species of tiny invertebrates live in moss cushions: insects, mites, springtails, nematodes, and tardigrades (those microscopic, nearly indestructible animals sometimes called “water bears” that scientists keep finding alive in ridiculous conditions). For these creatures, the moss provides shelter, moisture, and a stable little climate that doesn’t swing as wildly as the air outside. A tardigrade living in a moss cushion basically has a furnished apartment with climate control and a built-in water supply.

Note to creationists: This video mentions evolution at timestamp 2:27. You can think of how God made the tardigrade when you hear evolution being mentioned.

Indicators of Air Quality

Here’s something cool that connects back to what we learned earlier in this chapter. Because mosses have no roots, they absorb water and nutrients directly from the air and whatever lands on them. But that also means they absorb whatever pollution is in the air. They have no way to filter it out.

This makes mosses incredibly sensitive to air pollution, especially sulfur dioxide, a harmful gas released by burning coal and other fossil fuels that’s one of the main ingredients in acid rain. In areas with heavy pollution, mosses get sick, shrink back, or disappear entirely. Scientists actually use this to their advantage. They study where mosses are thriving and where they’re missing as a way to map air quality across a region. It’s like having thousands of tiny, free, living air-quality sensors scattered across the landscape. If the mosses are lush and healthy, the air is probably clean. If they’re gone, something is wrong.

Some Incredible Mosses You Should Know About

Before we wrap up, here are a few mosses and bryophytes that are too interesting to skip.

Luminous Moss (Schistostega pennata)

This moss glows. Not bioluminescence like a firefly, but something almost as cool. Luminous moss has specialized cells in its protonema that are shaped like tiny lenses. These cells collect dim light from the cave entrances and shaded rock crevices where this moss lives, focus it onto the chloroplasts inside, and reflect back unused green light. The result is an eerie, golden-green glow that makes the moss look like it’s lit from within. In the dim light of a forest cave, a patch of luminous moss looks like scattered emeralds glowing on the ground.

In some parts of Europe and Japan, luminous moss is associated with folk legends about fairy gold or goblin treasure hidden in caves. The “treasure” was just moss, but on a dark day in a damp cave, the glow is genuinely magical.

Resurrection Mosses

Several moss species can survive almost complete desiccation and come back to life when water returns. Tortula ruralis is one of the most studied examples. It can dry out to the point where its water content drops below 10% of its dry weight, sit in that state for months or even years, and then fully rehydrate and resume photosynthesis within about 20 minutes of getting wet.

Twenty minutes. From dead-looking brown husk to actively photosynthesizing green plant. That’s faster than you can cook a frozen pizza.

This kind of desiccation tolerance is rare in the plant kingdom. Most vascular plants die long before they reach that level of water loss. But for a bryophyte that can’t control its own water content (no cuticle thick enough to prevent water loss, no stomata to slam shut, no deep roots to tap groundwater), being able to survive drying out is an incredibly useful skill.

Chapter Wrap-Up

We started this book with angiosperms, the plants that have everything. We worked our way down through gymnosperms, which have cones but no flowers. Then through ferns, which have the plumbing but no seeds. And now we’ve arrived at bryophytes, the plants that stripped away nearly every feature we spent 22 chapters learning about and said, “We’ll make do without.”

No vascular system. No true roots. No seeds. No flowers. No cones. No fruits. No height to speak of. Just green tissue, rhizoids, and spores!

And it works. Mosses coat forests from the equator to the poles. Sphagnum alone stores more carbon than all the tropical rainforests on Earth. Liverworts clone themselves with rain-powered catapults. Hornworts keep growing their sporophytes from the base in a way no other bryophyte does. Luminous moss glows in caves. Resurrection mosses come back from the dead.

Twenty thousand species. Every continent.

For plants without plumbing, they’re doing just fine.