Mosses

I thought I had better visit some of the mosses I know before the snows came and covered them all up and it’s a good thing I did because we’ve gotten several inches over the last few days. You’ll notice in the above photo that mosses grow on soil, on tree bark, and on stone and we’ll look at some of all three in this post.

I thought I’d start with rose moss (Rhodobryum roseum,) which grows on stone and is one of my favorites. This pretty little moss likes limestone so when you see it you know you’re in an area where you might find other lime loving plants, like many of our native orchids. This moss forms dense mats and gets its common name for the aspirin size rosettes of leaves that terminate each stalk. They look like tiny flowers. This is the only example of rose moss that I’ve ever seen and I think it’s probably quite old.

Many mosses will grow on wood, stone or soil and delicate fern moss (Thuidium delicatulum) is one of them. This large stone was covered with delicate fern moss when branches fell on it. That didn’t stop the moss; it just grew right over the branches in its seeming mission to cover all the bare spaces it can find.

Delicate fern moss is a beautiful little thing that isnt as delicate as its name implies, but it certainly is fern like. Here it is crawling up and over one of those branches in the previous photo. The leaves of this moss are often bright yellow green in fall and are dull rather than shiny. It is fairly common and easy to find because it often forms very large mats.

Juniper haircap moss plants (Polytrichum juniperinum) look like tiny green starbursts. This moss grows on soil and is also very common in this area. I see them just about everywhere I go. Wet or dry, they always seem to look the same, even though many mosses change their appearance when they dry out.

When young the female spore capsule (sporangium) of juniper haircap moss is covered by a cap called a calyptra, which protects the spore capsule and the spores within. It is very hairy, and this is what gives this moss part of its common name. Eventually, as the capsule ages it moves from a semi vertical to a more horizontal position before the calyptra falls off.  The spore capsule continues to ripen and when the time is right it will open and release the spores. I’m guessing that at this stage the capsule is about the same diameter as a piece of cooked spaghetti. When it’s time to release the spores the end cap (operculum) of the now reddish brown, 4 cornered but not square spore capsule will fall off and the spores will be borne on the wind.

I don’t see splash cups on juniper haircap moss very often in this area but these plants had some of last season’s cups on them. Mosses in the Polytrichum genus have male and female reproductive organs on separate plants, so when you see these little cups you know you’ve found a male plant that is ready to reproduce, or already has. The male moss produces sperm in these splash cups and when a raindrop falls into the cup the sperm is splashed out. If there is enough rain water to swim in, the sperm will then swim to the female plant and fertilize the eggs. Each cup, about half the diameter of a pencil eraser, looks like a tiny flower with its rosettes of tiny leaves surrounding the reproductive parts.

Sometimes when you think you’re seeing moss you’re actually seeing a liverwort. The greater whipwort liverwort (Bazzania trilobata) lives happily on stones right along with mosses so you have to look carefully to be sure of what you’re seeing. A close look shows that it looks almost if it has been braided. Each leaf on this leafy liverwort is only about an eighth of an inch wide and has three triangular notches at its base. This is where the trilobata part of the scientific name comes from. It means “having three lobes.”

Tree skirt moss (Anomodon attenuates) does just what its name sounds like it would; it grows at the base of trees and makes them look like they’re wearing green stockings. It can also grow on soil or stone and can form extensive mats.

Tree skirt moss looks like it’s made up of tiny braided ropes when it’s dry. It is normally deep green but sometimes dryness can affect its color and shape. After a rain each tiny leaflet will pull away from the stem, giving the moss a slightly fluffier appearance than what we see here.

You might see dark green or purple spots on the bark of smooth barked trees like maple and beech and think you are seeing moss but this is another liverwort. There are about 800 species of frullania liverworts and many grow as epiphytes on the bark of trees and shrubs where the humidity is high. Epiphytic plants take nothing from the host plants they grow on, so this liverwort does no harm to trees. As it gets colder they turn color until they become a dark purple; almost black, so they are much more noticeable in winter than in summer when they’re green. Some can get fairly large but these examples were smaller than a tennis ball.

The tiny leaves of frullania liverworts are strung together like beads. Some frullania liverworts are said to be very fragrant but the few that I have remembered to smell didn’t seem to have any scent at all. This liverwort can cause something called woodcutter’s eczema. This eczema, called phytodermatitis (basically an itchy rash,) has been seen on loggers and others who regularly handle logs or cord wood with it on them. It doesn’t sound like anything serious and usually disappears in two or three weeks once the person stops handling logs with liverworts on them.

The name medusa moss (Hedwigia ciliata) comes from the way this moss looks like a bunch of tangled worms when it dries out. It is also called white tipped moss, because its branch tips are often bright white. This moss is fairly common and I find it mostly growing on stones in sunny spots. It always seems to be very happy and healthy.

Believe it or not this is the same Hedwigia ciliata moss we saw in the previous photo but this example was very dry. This is where the name “Medusa moss” comes from.

Stair-step moss (Hylocomium splendens) is a very beautiful moss that grows on stones and looks quite fragile, but I’ve seen it with icicles hanging from it so I can say with certainty that it’s a lot tougher than it looks. That is most likely why it grows as far north as the arctic tundra. It seems fairly rare here; this is the only example that I’ve seen.

When dry stair step moss has a slight satiny sheen to it, and that’s probably how it came by its other common name of glittering wood-moss. The name stair step moss comes from the way the new growth “steps up” off the midrib of the previous year’s branch.  Each year a new branch grows from the old and this growth habit allows stair step moss to grow up and over other mosses. It is said that you can tell the age of the moss by counting these steps, and from what I saw this branch that I found in 2014 would have been at least 5 years old.

White cushion moss (Leucobryum glaucum) gets its common name from the way it turns a whitish color when it dries out. When wet though, it can be dark green so it’s another moss that changes color.  This moss doesn’t reproduce by spores very often so it relies on vegetative reproduction. It grows on soil and turkeys and other animals that scratch at the soil help spread its pieces to other areas. I often see it scattered around some areas so it seems to happen regularly.

What this photo also shows are some fuzzy white growths on the white cushion moss that I’ve seen before but have never been able to identify. My gut feeling tells me that they have something to do with reproduction, but that’s little more than a guess. If you happen to know I’d love to hear from you. My moss books don’t mention them.

I found this pretty clump of what I think is flat glaze moss (Entodon cladorrhizans) growing on a dry ledge where soil had built up. This moss has shiny yellow green, overlapping leaves on stems that creep along whatever they grow on.  It also grows on rotting logs and tree trunk bases, mimicking the tree skirt moss we saw previously.

You can see some of the upright spore capsules (sporophytes) in this closer view of flat glaze moss. They are long and pointed when young and appear in late fall or winter. When mature they can be yellowish to reddish brown and will have a blunt, beaked end cap (operculum.) They are one of the things I used to help identify this moss, but I could still be wrong.

I hope you enjoyed meeting a few of the mosses I know. The next time you find yourself in a place like this with mosses all around I hope you’ll take the time to look a little closer. At this time of year anything green is welcome, and you might just see something beautiful enough to make you want to see more.

Moss grows where nothing else can grow. It grows on bricks. It grows on tree bark and roofing slate. It grows in the Arctic Circle and in the balmiest tropics; it also grows on the fur of sloths, on the backs of snails, on decaying human bones. It is a resurrection engine. A single clump of mosses can lie dormant and dry for forty years at a stretch, and then vault back again into life with a mere soaking of water. ~Elizabeth Gilbert

Thanks for coming by.