Beard Lichens (Usnea Lichens)

Beard lichen (Usnea lichen) on a branch
Scientific Name
Usnea spp.
Parmeliaceae (a lichen family)

Beard lichens are shrubby, branching, hairy-looking lichens that grow in tufts from a single point on tree branches. They look like tiny, leafless bushes. They are grayish green, and the branches are round in cross-section (not flattened). The tissues under the surface of the branches may be pink, red, or yellow (try scratching some of the surface cortex off of one of the branches). There is a flexible, elastic, cordlike central axis within the branches (try stretching one of the branches).

Apothecia (spore-bearing structures) are circular and the same color as the rest of the lichen, and they usually have bristled rims.

Soralia are often present, depending on species (soralia are small, rounded structures that produce tiny, fluffy-looking soredia, which are another type of reproductive body).

Globally, there may be at least 600 species in this genus. Missouri has about seven species in genus Usnea.

  • Missouri’s most familiar beard lichen is the bushy beard lichen (Usnea strigosa); it is widespread in eastern North America. Each stalk has many short hairlike branches growing at right angles to the stalk. It always grows on old wood or bark, usually on tree branches instead of trunks. Thus it often grows high up in trees.

Usnea species can be difficult to tell apart. To determine species with confidence, specialists often apply certain chemicals to a piece of the lichen and watch for a color change.

Like other fruticose lichens, or shrubby lichens, beard lichens are three-dimensional instead of having flattened leafy or crusty forms. Other fruticose lichens may look quite different, but they all lack a distinctive top, middle, and lower layer, since they are like little shrubs or trees.

A lichen is an organism that results when a fungus species and an algae species join together. Although the relationship between the fungi 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:

  • Spanish moss resembles lichens in the genus Usnea, but it is not a lichen, nor is it a moss. It is a bromeliad — a member of the pineapple family of flowering plants. It doesn’t grow in Missouri, but you might have seen it hanging like long, gray-green beards from trees in Florida and other southern states. It looks so much like beard lichen that its scientific name, Tillandsia usneoides, means “usnea-like tillandsia.”
  • Gold-eye lichen (Teloschistes chrysophthalmus), typically grows on branches in full sun. Like beard lichens, its branching lobes all arise from a central point, giving it a tufted appearance. The thallus may be grayish green like beard lichens, but it may also be yellow, especially near the cup-shaped fruiting structures. These apothecia cups are bright orange or yellow, and the rim of each is often surrounded by a thin rim the color of the thallus, occasionally with bristles radiating outward from the rim like eyelashes. This is a very attractive lichen, even though each tuft is only about an inch high.
  • Two species of twig lichens, or strap lichens (Ramalina spp.), are recorded for Missouri. At a glance, these look like beard lichens, since they grow in shrubby gray-green tufts. Unlike beard lichens, however, they have flattened, straplike branches.
Other Common Names
Old Man’s Beard
Bearded Lichens

Varies by species; most only grow to about 1 or 2 cubic inches. Groups of beard lichens, if they are crowded on a branch, may cover several square inches of substrate.

Where To Find

Statewide. Different species may have different habitat preferences and therefore different regional distributions.

Our most common beard lichen, bushy beard lichen (Usnea strigosa), typically grows attached to high branches in trees. If you are wanting to see this lichen, visit places with mature trees, and try looking on the ground: recently fallen branches lying on the ground may have beard lichens attached to them. Conservation areas with old-growth forests and woodlands along streams are a good bet.

Keep in mind that, depending on species, lichens that grow on wood and trees may be more common on trunks, or branches, or twigs, or at the very base of the tree, or on exposed heartwood. Some prefer smooth, hard bark as on hickories or maples, while others prefer rougher, softer bark as on black walnut or ashes. Oaks may offer a slightly more acidic substrate and be preferable to certain lichens for that reason. Some species prefer damp, decaying bark.

Some lichens require more light and are found in sunny areas, while others are best adapted to shady places. Corresponding to light and shade is the amount of moisture: some lichens need a damp habitat, while others can survive in drier situations.

Fruticose lichens are some of the first to disappear when a natural habitat is disrupted. Air pollution harms many lichens.

Beard lichens often seem to prefer branches on trees that are doing poorly or dying, and people sometimes worry that the beard lichen is the cause of the tree’s ill health. But actually, the lichen is simply taking advantage of a sunnier habitat caused when a tree is losing its leaves. Even though lichens may cover large areas of trees, they are not parasites, and they do not damage trees.

Life Cycle

Lichens can reproduce vegetatively or sexually. Vegetative (asexual) reproduction occurs when a piece of a lichen breaks away and begins growing independently elsewhere.

Some, but not all, beard lichens can reproduce vegetatively by producing soredia, which are small, granular packets of the fungus and algae. Groups of soredia often look fluffy or mealy on the outer surface of a lichen. These can easily break off and start a new lichen elsewhere. Soredia are often formed in rounded structures called soralia.

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 sperm and ova that occurs in the reproductive structures of the fungus. In Usnea, spores develop in, and are released from, structures that look like flattened disks; these are called apothecia.

Bearded lichens in genus Usnea have been used medicinally for a variety of applications. Some are being studied for modern pharmaceutical uses. With their antimicrobial properties, they may also be toxic.

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 beard lichens, painted green or perhaps in autumnal colors, to represent trees and shrubs in their dioramas. You can usually buy them in a variety of colors at craft stores.

Lichens contribute to a beautiful landscape. In rich forests, beard lichens grow in interesting, mysterious masses on tree trunks, limbs, and fallen branches.

Because lichens, with their soft, absorbent tissues, are extremely sensitive to air pollution, they are good indicators of air quality. Scientists use them as sentinels of environmental health.

Some species of flying squirrels build nests out of beard lichens and other fruticose lichens.

Because many lichens provide cover for several types of insects, insect-eating animals often focus their hunting on lichen-covered places on trim limbs and trunks. Birds that forage for insects among lichens include nuthatches, the brown creeper, chickadees, titmice, woodpeckers, and numerous vireos and warblers. Other animals that look for insect prey among lichens include several types of spiders and the larvae of green lacewings.

Interestingly, beard lichens, which have a shrubby (fruticose) form, are in the same family (Parmeliaceae) as many of our most familiar leafy (foliose) lichens, including greenshield lichens, speckled shield lichens, and ruffle lichens; in fact, the Parmeliaceae is often called the shield lichen family. Remember that growth form (such as crustose, foliose, and fruticose) is not a taxonomic designation, just as the terms tree, shrub, vine, or wildflower don’t identify vascular plants, except in a general descriptive way. The rose family, for instance, includes woody trees, woody shrubs, and nonwoody plants, for example cherry trees, rose bushes, and strawberries.

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Similar Species
About Mosses, Liverworts, and Lichens in Missouri

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.

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