Tree Mosses (Climacium Mosses)

Media
Climacium moss, or tree moss, closeup showing treelike growth form
Scientific Name
Climacium americanum and Climacium kindbergii
Family
Climaciaceae (tree or climacium mosses; a dendritic moss family)
Description

Tree mosses in genus Climacium look like miniature pine or palm trees, complete with tiny upright trunks and long, slender branches clustered at the top. They are easy to identify by their growth form. They form dense, thick mats in moist, shady places.

The growth habit of tree mosses sets them apart from other mosses in our state. While most mosses fit into the categories of either pleurocarpous (carpet-forming) or acrocarpous (cushion-forming), tree mosses are dendritric (dendroid or treelike). (For simplicity’s sake, tree mosses are often grouped with the pleurocarps.) A colony of tree mosses looks like a dense, lush, rich green mat of tiny trees:

  • The brown, leafless primary stems creep horizontally across the ground, just under the soil surface.
  • The secondary stems grow upright, like tiny trunks, from the primary stems to about 2 inches tall. The secondary stems do not split into branches.
  • Starting about halfway up the secondary stems, there are several long, slender tertiary stems, resembling tree branches, which are up to about 1 inch long and unbranched. These tertiary stems taper to their tips and are densely covered with clasping green leaves.

Missouri has two species of tree mosses:

  • Pine moss, also called American pine moss, American tree moss, or American climacium (Climacium americanum), can be found statewide on moist, shaded soil, usually on ledges and at the bases of bluffs. Its treelike growth habit is unlike any other species in this habitat. This is the more widespread of our species.
  • Kindberg’s climacium (C. kindbergii) has sometimes been considered a subspecies or variety of C. americanum; it is less common, lives in wetter habitats, such as along shallow, rocky streams, and is less erect and less densely branched than its relative.

Tree mosses do not frequently produce sporophytes. When they are produced, there are usually 5 or 6 per secondary stem (per tiny “tree”); the capsules are cylindrical, reddish brown, and arise on thin setae (stalks) from various points on the sides of the secondary stem.

Learn more about Missouri’s mosses on their group page.

Similar species: At a glance, several other mosses may resemble tree mosses in color and overall texture, but if you pay attention to the unique growth form of tree mosses, you won’t have any trouble identifying them.

Be aware that there are several other types of mosses with “tree” as part of their name. In most of these cases, the mosses were so-named because they typically grow on trees (not because they resemble trees). For example, tree-skirt or tree-apron mosses usually live on the bases of tree trunks, in what some people have jokingly termed “the canine zone.” This confusion of names is another reason why it’s a good idea to start learning scientific names.

Other Common Names
Pine Mosses
Dendritic Mosses
Size

Height: 2 to 3 inches.

Where To Find

Statewide in appropriate habitats.

Easy to identify, tree mosses are large and commonly form big, lush mats in very moist, shady areas. They usually grow on soil.

Our two species of tree mosses may be separated, with a good amount of confidence, on the basis of habitat. Our more common species, C. americanum, is usually seen on ledges and bases of bluffs, in moist, shady places. Our less common species, C. kindbergii, is confined to wetter habitats, such as soils along shallow, rocky streams, or in wetlands.

Tree mosses are characteristic plants of stable bedrock embankments in Ozark streambank and riverbank natural communities, and in bottomland and sinkhole flatwoods.

Tree mosses, along with fern mosses (Thuidium spp.), are among the dominant plants in Missouri’s forested fen natural communities.

Common in the appropriate habitats.

Life Cycle

Tree mosses do not often form sporophytes, so their reproduction and spread is usually through vegetative means: by their creeping stems, and when a portion of the plant breaks away, gets moved elsewhere, and continues growing as a separate plant.

Who doesn’t like to make discoveries? When you first see a tree moss — and we mean, really see it, and know what you’re seeing — we’re sure you’ll be delighted: “Hey, this is one of those nifty things called tree mosses!”

As they have with certain types of shrubby lichens, model train enthusiasts sometimes use tree mosses to represent trees in their dioramas.

In the past, tree mosses were sometimes used as a decoration for women’s hats.

The forested look of tree mosses is created by numerous upright secondary stems that look like tiny trees, while the primary stem lies horizontally along the ground. Well, bonsai artists achieve a similar look with real trees using a technique called “rafting”: Using a single, small tree, they remove all the branches except the ones along one side of the trunk. Then, they pot the tree sideways, with the trunk lying on its side on the soil surface, and they train the remaining branches to grow upright like trunks. The eventual result is a bonsai forest in a single pot — and it can really look spectacular. Rafting can happen in nature, too, when a tree falls over but enough of the root stays in the ground to keep it alive, and the surviving branches grow upright and look like trees themselves.

The carpets and mats formed by mosses and other small plants form a microhabitat where many types of insects and other invertebrates live. Earthworms, centipedes, sowbugs, springtails, snails, and a wide variety of other small animals live in and around mosses. Tartigrades, or water bears, are curious microscopic eight-legged animals that often live among mosses. Shrews, salamanders, frogs, tiny snakes, and other insectivores hunt for a variety of small animals among the mosses.

Tree mosses and fern mosses (Thuidium) are some of the mosses preferred by female four-toed salamanders for nesting sites along small, fishless creeks. Thick mats of these mosses overhanging the water are ideal for this species, whose females remain with the eggs for about four weeks, until just before hatching time.

Many kinds of birds, as well as mice and other mammals, use moss in nest building, relying on its ability to cushion fragile eggs and delicate, naked young; to insulate against cool weather; and to camouflage the nest, concealing it from predators. Even bumblebees use mosses in their nests.

Mosses that live on the damp soils in lowlands are very important in preventing soil erosion. They also help to build up soils, trapping organic materials in their network of branches, adding nutrients to the earth that can be used not only by the mosses but also by larger plants such as wildflowers and trees.

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