Field of Science

The Peat Moss Saga (Part 1)

Members of the moss genus Sphagnum grow in wet areas and are typically the dominant plants growing in bogs. They can be recognized by their distinctive growth form, which includes a head or capitulum of multiple branches at the apex. The branches that grow on the mid and lower portion of the stem are grouped into fascicles or bundles. Within these groups are branches that are pendant and others that are perpendicular to the stem. When examining the leaves with a hand lens it can be seen that they are curved at the apex into a scoop shape. Determining the species of Sphagnum can be notoriously difficult. It requires dissection of the plant to make a leaf cross section and a compound microscope. However once you have seen peat moss in the wild they are pretty unforgettable and the genus is easily recognized.

Sphagnum is the most economically important group of mosses and has a number of unique features with associated fun facts. Tune in Friday for the continuation of our journey into the world of the peat moss.

Moss Poetry

Mosses also serve as poetry muses. This poem was brought to my attention during discussions of my blog in my Science Communication Seminar. I think that it is a great verse and presents vivid imagery of moss. Enjoy!

Moss-Gathering by Theodore Roethke
To loosen with all ten fingers held wide and limber
And lift up a patch, dark-green, the kind for lining cemetery baskets,

Thick and cushiony, like an old-fashioned doormat,

The crumbling small hollow sticks on the underside mixed with roots,

And wintergreen berries and leaves still stuck to the top,—
That was moss-gathering
But something always went out of me when I dug loose those carpets

Of green, or plunged to my elbows in the spongy yellowish moss
of the marshes:
And afterwards I always felt mean, jogging back over the logging road,
As if I had broken the natural order of things in that swampland;
Disturbed some rhythm, old and of vast importance,

By pulling off flesh from the living planet;

As if I had committed, against the whole scheme of life, a desecration.

Tools of the Trade

I would like to introduce you to my hand lens or, as geologists like to call them, a loupe. This is a highly useful piece of equipment that I always take with me when on a hike or out looking at plants. It is great for zooming in on the tiny mosses that I love so very much. I guess that I could also use it to look at other interesting tiny things like insects, but they move a lot faster than mosses and thus may be more challenging to catch.

Hand lenses take a little practice to get used to using them. Proper technique is to hold the lens up to one eye and close the eye that you are not using. Usually I touch my hand to my face to keep the lens from wavering. Then holding the lens as still as possible, bring the specimen that you are looking at up to the lens and your face. Bracing your hands together while doing this will help decrease movement. Then you can make minor adjustments to get the part of the moss in focus that you are most interested in.

If you are in the market for a hand lens I can highly recommend those made by Bausch and Lomb. Hands lenses also come in a variety of magnifications from 7X to 20X. Most botanists that I know have 10X lenses, which is sufficient zoom for most small creatures. I have a 14X lens. The added magnification is great, however the trade off is that it has a smaller lens surface and a shorter focal depth. Be sure to put your lens on some type of string or lanyard to hang around your neck. Otherwise this small item can be easily lost.

The Mother-In-Law's Cushion

This is another one of the names for Leucobryum albidum, as mentioned on Monday. The story goes that this moss can grow in patches that are large enough to use as a seat on the forest floor. When you touch the top of this moss cushion it feels soft and dry. However you should only offer this seat to your mother-in-law. (Two assumptions of this tale are that you have a mother-in-law and that you like playing tricks on her.) When she sits down on this moss she will experience one of the benefits of growing in a cushion shaped colony. All of the individuals packed together function as a sponge and store water within the colony, so that there is moisture available for the moss to undergo photosynthesis even when it is dry. Having sat on this cushion your mother-in-law will end up with a very wet rear. Thus Leucobryum albidum also has been called the mother-in-law's cushion.

A Moss of Many Names

I have heard this moss species referred to as the white moss, the pincushion moss and mother-in-law's cushion. The scientific name for this plant is Leucobryum albidum. Based on the etymology of its name, white moss is probably the most appropriate. The prefix of the generic name comes from the Greek word leuco or leuko (spelling varies) which means white. {As I read over this post for a final check I was reminded of the father in the movie My Big Fat Greek Wedding. He has a habit of connecting all words in English back to Greek roots. Just thought that I would share so that you too can read the post with a fun Greek accent.} The specific epithet albidum comes from the Latin word albus, also meaning white. So the scientific name tells us that this is a white, white bryum-like moss and the name describes this plant quite well. This moss has a distinctive white sheen and can be found on rotten logs or nestled up next to exposed tree roots as is this patch. I would say that it is one of the whitest moss that you will see in the forests of Connecticut, which makes this species easily recognized. Stay tuned for a discussion of an alternative name for this moss, the mother-in-law's cushion.

Where do the Mosses and Lichens Live?

All of the photographs that I have posted thus far, excluding the photo of Funaria hygrometrica, are of mosses and lichens growing at the James L. Goodwin State Forest in Hampton, Connecticut. It is one of the places where I lead moss walks during the summer. I went for a hike there a couple of weeks ago and took the pictures that I have been posting. So if you are interested in seeing these creatures in the flesh it is a nice place to visit. It is also a great place to go canoeing! (My shameless plug for the free and open to the public state forest.) When I was out canoing we spotted mosses growing on the logs and tree branches sticking out of the middle of the lake, which was very cool. I don't have any pictures of them, but if I am out on the lake again I will be sure to take some.

The Hairy Cap

Based on a request from last week, I have posted a photo of the hairy cap of Polytrichum commune. The technical name for this cap or hood is a calyptra (plural=calyptrae). It typically sits atop the moss sporophyte and covers the capsule. This highly hairy hood (try saying that 3 times fast) is a characteristic that is shared by members of the genus Polytrichum. Calyptrae may be found year round, but are most prevalent during the late summer and early fall in Polytrichum commune. The stalk, capsule and calyptra are attached atop the leafy portion of the moss. Check out the post from October 8th and imagine the structures shown today growing out of the apex of the leafy plant. If you have located the hairy calyptra you have found a Polytrichum.

Reindeer Lichen

This highly branched, 3-dimensional lichen is in the genus Cladina.

Is it a Moss?

It is small, greenish, growing on a tree, but is it a moss? Unfortunately it's not, no matter how much it might envy our green mossy pals it doesn't qualify. This critter is a lichen. Lichens are symbiotic organisms which consist of a fungus and an alga, either blue-green or green. Typically fungi are saprophytic, meaning they feed on dead or decaying material and are not able to produce their own food. This fungus has a different lifestyle and is a farmer. No digging through the trash to find sugars for him. Instead this fungus houses a alga which it keeps happy by supplying water, air, and sunlight. With that combination of supplies that alga undergoes photosynthesis to produce sugars that the fungus uses to live. It is a pretty smart system and works out well for both of the partners. The lichen pictured here is Flavoparmelia caperata, the common greenshield lichen. This species typically grows on bark and can be found across the eastern United States. So when you are out looking for mosses keep an eye out for the lichens as well.

Moss Snorkels

WARNING: This information is inaccutate. Please see this more recent post for additional information.

Mosses along with all other plants need water, sunlight and air to live. However mosses don't have roots, which is the usual way that plants move water into their bodies. Instead they take up water from the environment through their outer layer of cells. They also exchange gases through this layer of cells. This causes a dilemma. Mosses have to drink and breathe through their "skin". Polytrichum commune and its close relatives have come up with a ingenious solution to this problem. They have snorkels. Okay they are not technically called snorkels, they are called lamellae, but that is what I like to refer to them as when I explain how they work. When the moss leaves are wet their entire surface is covered by a film of water. Gas exchange cannot happen through the water, but the snorkels stick out above the water and are dry at the tips to allow for gas exchange. The image that I posted is a section through a Polytrichum commune leaf, with the top side up and the bottom side down. The shiny white cells make up the thickened portion of the leaf and each green filaments of cells is a snorkel. Then wet, the spaces between the snorkels are flooded with water and the upper-most snorkel cell is exposed to the air. If you zoom in on this picture you may be able to see that the upper-most snorkel cells have a notch or divot in them. This is a microscopic clue that tells us this leaf is definitely from Polytrichum commune.

Mugshot of a Moss

Based on a comment from last week I decided to introduce Polytrichum commune, the common hair capped moss (hairy cap not pictured). This species can be found in wet areas of yards or meadows across North America and beyond. I discovered this individual growing in a wet spot next to a picnic shelter. This species is easily recognized by its stout appearance and star shaped spray of leaves, which can be seen when viewed from above. The individuals are pretty large as far as mosses go. The one pictured here is about 4cm tall and they can reach heights of 30cm or more. However those that I have seen around Connecticut are usually not skyscraper sized and range from 4 to 10cm. This is a species that I run across nearly every time I am out looking at mosses.

Why are Mosses cool?

Have you ever been walking through the woods and noticed a patch of green on the side of a tree, rock or fallen log? Well you might have spotted a moss. Mosses are plants, typically small, and come in a variety of shapes and shades of green. One of the great things about them is that they are more and more interesting the closer that you get to them. What appears to be a swatch of green at a distance is actually a miniature forest up close. This is an image of a colony of Funaria hygrometrica, the cord moss, that I have growing in the laboratory. The mosses growing outside in Connecticut are currently not very photogenic due to the drought and heat wave we are having. But don't worry, mosses are quite resilient and most types can come back to life after drying to a crisp.