Moss is a prehistoric plant. It has no flowers, no roots, and it reproduces the same way mushrooms and other fungi do, using spores. While many people consider moss to be a sign of too much moisture (which it can be), I love how it looks on my chicken coop’s thatched roof.
Moss has been around for a really long time, some estimate 470 million years, and it evolves 2 to 3 times more slowly than most other plants. Unlike lichens, hornworts, and liverworts, which are also really old, but more complex, mosses are too fragile to leave behind much of a fossil record. Recent research, however, has shown that mosses may be responsible for the Ordovician ice age, some 200 million years before dinosaurs even existed!
Currently, there are over 12,000 varieties of moss. Sphagnum, or peat moss, is commonly used as burnable fuel, in floral arrangements and crafts, and it has one rather odd characteristic: peat moss alternates living cells with dead cells. Those dead cells are used to store water. Using this method, some mosses can absorb up to 20 times their weight in water! And water is critical to moss fertilization. Moss can tolerate being completely dried out for months, but one quick rain and BAM! They are back in business!
When I lived in Virginia, trying to keep moss out of the lawn was a constant battle. My neighbors thought I was nuts when I finally stopped fighting the moss and actually started encouraging it to grow. Moss prefers acidic soil, which Virginia has plenty of, so I used equal parts moss and sour milk in a blender and poured it wherever I wanted more moss. End result: my “lawn” was always flat, always green, always soft, and never hung on to fallen leaves. It looked and felt lovely. In Japan, entire gardens are dedicated to the quiet beauty of mosses. Moss can be used to cover stones and other structures, softening the edges and adding a sense of tranquility. Moss can also be used to create living art that may surprise you!
So what is this tiny primitive plant we call moss?
The green mats we see covering rocks and roofs and filling cracks in sidewalks are actually millions of tiny plants clustered together. Moss is profoundly simple. It is actually easier to describe moss by what it isn’t: no roots; no flowers; no seeds; no vascular tissue. Each moss plant consists of simple leaves that are only one cell thick, with no air pockets, and a stem that can be branched or unbranched. After a moss plant is fertilized, you can see a tiny stalk emerge with a single capsule at the end. This capsule contains spores called sporophytes. One species of moss, Dawsonia, has a stalk that grows up to 20 inches long! You may also be surprised to learn that mites and springtails act as pollinators for mosses! Male and female mosses emit different aromas to attract these helpers! Who knew?!!? There are also mosses that can reproduce vegetatively, using a leaf or branch that has broken off to start a new plant.
The weirdest thing about moss reproduction is something called nannandry, or dwarf males. This means that male spores that land on or close to a female spore become dwarf-sized, while male spores that land too far away become female-sized. Scientists believe this is because larger spores are more likely to be carried closer to a female by external means. Weird, right?
While there are no actual roots, mosses do anchor themselves to surfaces using threadlike rhizoids. Contrary to popular belief, mosses do not feed on the substrates to which they are attached. They do, however, secrete acids that dissolve the rocks and wood they cover. Mosses get their water and nutrients by absorbing them directly into their cells, often as rain falls on them or water flows over them. Moss plants also use photosynthesis for some of their energy. Mosses can be found in sun or shade, wet areas, on alpine rocks, and even on sand dunes! While mosses are commonly found on roofs, streets, and sidewalks, they are generally classified according to these traditional substrates:
If you were a moss, what would your substrate be?
Slow growing moss, cloaking everything it touches, has inspired some funny words:
Finally, the old rumor about moss growing on the north side of trees is bogus. Moss grows on the wet side.
You can grow a surprising amount of food in your own yard. Ask me how!