Dixie reindeer lichen is well-known, widespread, and takes the form of pale yellow-green cushions. These much-branching cushions are the reproductive structures (podetia) of the lichen. The branches of reindeer lichens are round in cross-section. The spore-producing organs, when present in reindeer lichens, are tiny, brownish knobs at the tips of the branches.
Less noticeable, the main body of the lichen (the thallus) consists of green, scalelike structures (squamules) that spread like a mat over the surface of the soil; these squamules often don’t last long and may be gone by the time the branching podetia develop.
There are some close relatives (also called reindeer lichens) that look similar, but this species mostly branches in relatively narrow Ys (pairs); each branch is rather slender and usually ends in only two tiny, pointed tips; and it’s usually difficult to pick out centralized main stalks (trunklike axes). Also, compared to other reindeer lichens in our state, it looks more delicate. The overall color — pale yellow green (as opposed to silvery gray or pale greenish gray) — is also important for identification. The color reflects the chemical properties of this lichen. Specialists often apply certain chemicals to a sample of a lichen, then watch for color changes, to verify their IDs.
Like other fruticose lichens, or shrubby lichens, reindeer lichens are three-dimensional, in this case resembling a tiny leafless shrub. Unlike crustose and foliose lichens, which are basically flat or leaflike, fruticose lichens don’t have a distinctive top, middle, and lower layer, since they are like little shrubs or trees. They have a well-developed three-dimensional growth pattern.
Despite some of the common names, lichens are not mosses; in fact, they are not even plants. A lichen is an organism that results when a fungus species and an algae species join together. Although the relationship between the fungus and algae is quite intimate and integrated, the lichen that is formed does not much resemble either of the components. Learn more about lichens on their group page.
Similar species: Of Missouri’s three species in genus Cladina, Dixie reindeer lichen is the most common and widespread. The other two species of reindeer lichens are distinguished by overall color and distinct branching patterns:
- Tree reindeer lichen (C. arbuscula), like reindeer lichen, is pale yellow green (as opposed to silvery gray or greenish gray). A big difference is that it mostly branches in whorls of 3s or 4s, not Ys (pairs). Also, there are definite main stalks that give rise to the bushy branching tips.
- Gray reindeer lichen (C. rangiferina) is bright ashy or silvery gray, and the branches usually end with 3 or 4 tips; these, at least partly, bend to point in the same direction — as if they were blown by a strong wind, or combed, and froze in that position. There are usually obvious main stalks that give rise to the bushy branching tips.
Many scientists group the various Cladina species in with genus Cladonia. Counting all these “cladoniform” lichens together, Missouri has about 40 species (37 in genus Cladonia plus 3 traditionally placed in genus Cladina). Most of these, at some point in their life cycle, exist as patches of rather unspectacular greenish or grayish, scalelike squamules. The various shapes, colors, and textures of the fruiting bodies are important for identification in this group.
Each cushion may be several inches wide and tall. Cladoniform lichens, as they spread, may cover several square inches of substrate.
Statewide in appropriate habitats.
Habitat and Conservation
Dixie reindeer lichen is widespread and common in eastern North America. It almost always grows on soils, usually in dry woods. Only rarely does it grow on decaying bare wood.
Status
This is the most common of our species of reindeer lichens.
Life Cycle
Lichens can reproduce vegetatively or sexually. In reindeer lichens, vegetative (asexual) reproduction is probably most common. It can occur whenever a piece of the lichen breaks away and is moved to another location, where it can begin growing independently elsewhere.
Lichens, especially when dry, may break easily, and the fragments may be transported to new locations via wind or water. The various reindeer lichens, when dry, become very brittle; when, say, a deer steps on one with a muddy hoof, portions of the lichen may easily be dispersed to new locations.
The fungal component of a lichen can reproduce sexually, in the same manner as other fungi: the spores they create are the result of a fusion of gametes (sperm and ova) that occurs in the reproductive structures (apothecia) of the fungus. Apothecia are uncommon in Dixie reindeer lichen, but when they do occur, they look like tiny brown knobs on the branch tips.
Human Connections
The names of this lichen are revealing. The genus-level common name, reindeer lichen, came about because, in the far north, members of this group are an important winter food for deer and caribou. The “clad-” root of the scientific genus name, means “branching” — a good choice for these much-branching lichens!
Reindeer lichens are a group that have been used medicinally for a variety of applications. With their chemical properties, they may also be toxic.
Can you eat lichens? Reports vary. Certain types of reindeer lichens, in some parts of the world, have been eaten in the past, especially as a survival food. But many lichens contain toxic chemicals, so we do not recommend eating them. Reportedly, when used as a food, the flavor of reindeer lichens is not worth recommending, anyway.
When dry, shrubby lichens such as these have been used as tinder for starting fires.
Like other lichens, shrubby lichens have been used to make dyes for clothing.
Model railroaders and others who create miniature landscapes often use dried reindeer lichens, colored bright green or perhaps in autumnal colors, to represent trees and shrubs in their dioramas. Flower arrangers also find many decorative uses for them. You can buy them in a variety of colors at craft stores.
Reindeer lichens contribute to a beautiful and interesting landscape.
Because lichens, with their soft, absorbent tissues, are extremely sensitive to pollution, they are good indicators of environmental health.
Ecosystem Connections
The sponge-like cladoniform lichens aren’t called reindeer lichens for nothing. Deer and their relatives eat them, especially in winters up north. Caribou rely on them for nearly all their winter diet. They dig through the snow to get at them.
Some species of flying squirrels build nests out of fruticose lichens such as these.
Lichen moth caterpillars feed on lichens, and so do lichen grasshoppers, which live in Missouri’s glades. Both the caterpillars and lichen grasshoppers are camouflaged to blend in perfectly with lichen-covered rocks and soils.
Both the adults and caterpillars of the little white lichen moth (Clemensia albata) are lichen-camouflaged. The caterpillars of this easy-to-overlook species (the only species in its genus) eat lichens.
In desert, tundra, and alpine habitats and regions, lichens may be the dominant form of life. It is estimated that 7 percent of Earth’s surface is covered by lichens.
Soil-living lichens are important stabilizers, preventing soil from being washed away by rain or blown by the wind. Although reindeer lichens seem very fragile and only delicately connected to the ground, they and their surrounding community of humble mosses, lichens, and small vascular plants help heal lands that have been disturbed. Thus they are beneficial on eroded or overgrazed pasture land, or places where a tree has been toppled, and the roots and accompanying soil tipped out of the earth.
Mosses, liverworts, hornworts, and lichens seem rather similar, but these organisms are in very different groups. Mosses, liverworts, and hornworts are small, low plants usually found in damp habitats. Unlike more familiar plants, they lack veinlike structures and do not produce flowers or seeds — instead, they produce spores. Meanwhile, lichens are not plants at all: they are a collection of different fungi that have photosynthetic algae living within their tissues.