There are different ways to go about enjoying mosses: from a distance they form a richly textured background in a forest, or a carpet across an abandoned sandy area, mixed with reindeer lichen. The color spectrum of mosses is heavy in the greens, but you can also find red or coral tinged mosses, or ones that have a pale gleam. But mosses are more than just pretty scenery—they’re an important and interesting part of our ecosystem. Combined, bryophytes (mosses and liverworts) unite with lichens and algae to take up about 14 billion tons of carbon dioxide annually—an important distinction on a planet with a big CO2 problem leading to a warming climate! That’s a really staggering figure; it means that the entire output of forest destruction and biomass burning is being offset by these abundant but often overlooked organisms. Find out more on this research from the Max Planck Institute of Chemistry and a related article from the journal Natural Geoscience.

Mosses are no slouches in this department. Members of the moss genus Sphagnum (commonly known as peat mosses) are believed to sequester more carbon than any other genus of organisms on the planet (Gathering Mosses, by Robin Wall Kimmerer). And these cryptogams are superstars in the nitrogen fixing department too—they are able to take nitrogen from the air and convert it to a form that can be easily taken up by plants. The Max Planck Institute scientists estimated that N fixation by cryptogams was about 50 million tons annually. That’s a lot of plant fertilizer.


Many habitats on Nantucket are downright harsh for bryophytes. The shifting sands of the dunes and the dry, sandy, acidic soils of our moors, grasslands, and heathlands all pose a serious challenge—lack of moisture, or wide variation in moisture levels. Mosses, unlike vascular plants, cannot transfer water through their tissues for long distances, so they can’t grow very big. Not to mention, mosses do not send pollen out into the air or transport it by producing nectar and food for pollinators, as vascular plants do; they require water for their gametes to get out and swim to the nearest egg! So, a layer of moisture is necessary for moss reproduction. This season’s heavy rains and cool weather mean that mosses are flourishing and will have no problems with that. So, let’s take some time to get to know a few of the island’s common and (fairly) easily identifiable mosses.

In between bouts of rain and wind, Spring is a great time to get your boots on and take a better look at the mossy world and its minuscule wildlife (mites, springtails, etc). If you have a hand lens or magnifying glass, that’s a helpful addition to your “Island Bryophyte Adventure,” but if you don’t, here are a few mosses you can learn to recognize and appreciate with the naked eye.

Fire Moss (Ceratodon purpureus)

Fire moss, also called “red shanks” for its purplish red stalks, is common in dry, disturbed habitats on island. Photo: K.A. Omand

is moss is on fire right now, living up to both its common and scientific names, with an abundance of purplish-red stalks waving in the breeze. Look for this tiny moss in open sunny areas with disturbed sandy soil. You can even find this one downtown or in your yard. Or, if you happen to be in Antarctica. It’s tolerant of tough conditions and is a common colonist after a fire, or in sandy areas like road edges, and is found on all seven continents. How can you recognize it? This is the best time of year to learn, as the characteristic reddish stalks, or setae, rise up above the nondescript carpet of moss vegetation. Each stalk sports an elongated capsule.

You might have started noticing this moss in February as the stalks started to pop up, and its capsules mature by late Spring. Like early season wildflowers, this species is quick to start up and fast to finish and fade in the heat of summer…if we get any heat this summer, which remains to be seen… Researchers have found that fire moss has an interesting reproductive slant—while it still requires water to transport its gametes for sexual reproduction, it also has tiny visiting organisms, known as springtails or Collembola spp., that appear to move from one individual to the next and transport gametes—just like the transfer of pollen from plant to plant by insects feeding on flowers. More info on springtails and moss fertilization here.

Once fertilized, the egg “sprouts” into a sporophyte, growing atop the original female gametophyte, sending up a seta topped with a spore-filled capsule. The spores may be dispersed by wind or water, in turn growing into new gametophytes, that in turn produce gametes, completing the cycle of alternating moss generations. For a better understanding of how moss life cycles work, check out this link with a handy illustration. Ferns and algae share a similar life cycle. It may seem alien and complicated to us, but it has worked for these groups of organisms since ancient times.

Peat or Bog Mosses (Sphagnum spp.)

A peat or bog moss on a hummock in a red maple swamp at Masquetuck, with a reddish coloration and broad branches. Photo: K.A. Omand.
Another bog moss at Masquetuck, in a muddy stream edge along the trail, may be a different species; check out the narrower branches and a stellate or star-shaped top, and a lusher green color. Photo: K.A. Omand.

Happy to inhabit shrub swamps and forested swamps, Sphagnum spp. also form the bulk of vegetative material in Nantucket’s bogs. Over time, Sphagnum mosses decay and form deep layers of compacted organic material. The living layer of moss grows in a spongy mat at the surface, supporting a variety of bog orchids, cranberry vines, sundews and pitcher plants. Sphagnum mosses and huge bogs like this exist in vast expanses in far northern latitudes (where they happily sequester equally vast amounts of carbon). The specialized plant species growing in them could not survive without these squishy mats. On Nantucket, the four-toed salamander (Hemidactylium scutatum) is limited to habitat with vernal pools and thick sphagnum mats, where the female salamanders lay their eggs. Without the thick moisture holding mats of sphagnum and the vernal pool habitat, there would be no four-toed salamanders on island. In fact, this salamander was undiscovered on Nantucket until documented in 2009 by Andrew Mckenna-Foster, working for Maria Mitchell Association.

Pincushion Moss (Leucobryum glaucum)

Pincushion moss grows in tight compact clumps on the forest floor; easily dislodged from the ground by deer or foot traffic, it is able to form rootlik structures from its body and re-attach if the new site is hospitable.

Pincushion moss is quite common in forests on the mainland, but harder to find here on Nantucket. However, its pale tint makes it easy to learn. The scientific name is highly descriptive for this species, Leuco meaning “white or lacking colour” from the Greek leukos, bryum from the Latin bryon, for moss, and glaucum from the Greek, glaukos, meaning “gray or gleaming.” My grad school instructor in Lichens and Bryophytes, Ralph Pope, got a particular kick out of that name. “How many ways do you need to say that it is whitish!?!” he would ask. But it is memorable.

The coloration of this moss–often sage or seafoam green–and the tight domed pincushion shape makes it truly stand out in a gloomy forest. During one of Ralph’s field classes, a large clump of this moss had been dislodged by foot traffic. One of the students submerged it in water, and by the end of the class, it had roughly quadrupled in weight, demonstrating the remarkable ability of mosses, even upland mosses, to absorb water quickly during wet weather. Large areas of moss, releasing their moisture to the air, both add to the ambient humidity of a forest or bog, and help moderate the temperature like air conditioning…all the while fixing Nitrogen and sequestering carbon!

Broom moss (Dicranum scoparium)

The side-swept hairlike leaves of broom moss give it the common name: think of a broom that has been used too long, so that all the fibers are bent the same way!

Like the pincushion moss described above, broom moss also forms domed clumps, but it is a vivid shade of spring green, and the individual moss plants are far less tightly packed. As a result, the moss bunches look softer and more unkempt, and if you press upon them lightly, you can feel that they are less compact and more pillowy. Also like pincushion moss, the broom moss individuals have curving leaves at the top, but the leaves on a broom moss are much more flamboyantly curved, long and swept to the side. The recent wet weather makes these mosses take on more of a neon, yellowy green—not whitened. Pincushion moss and broom moss often grow together, so you can compare the two forms and shades of green. But you will find that broom moss is much more common on Nantucket.

Hope you enjoyed this mini-moss tour, and can get out to explore the mosses in person. You should have some opportunities to find mosses in your neighborhood, or on a conservation property near you.