Usnea Identification: The Stretch Test and Look-Alikes

To identify usnea, take one pale gray-green strand and pull it gently from both ends: the outer layer splits and a white, elastic central cord shows inside. Wikipedia's Usnea article describes this elastic axis running through the middle of the thallus as the genus's most distinctive feature, and it is the one test that separates usnea from almost everything that looks like it.

Usnea is a lichen, a partnership of a fungus with algae or cyanobacteria (Wikipedia, Lichen), not a moss or a plant. It grows as small shrubby tufts or as hanging beards on bark and branches. Colors run from straw, yellow-green and pale green to grayish-green, and a few species are reddish (Wikipedia). The genus has roughly 130 species across temperate and tropical regions of both hemispheres.

The Woodland Trust, one of the top results for this search, describes beard lichens as fruticose lichens that grow like mini shrubs or tassels anchored to bark, consistently pale gray-green, sometimes with disc-like fruiting bodies.

• Pick a strand that is already on the ground or on a fallen branch.
• Hold it between the thumbs and fingers of both hands, about 2 cm apart.
• Pull slowly. On usnea the gray-green outer layer cracks and separates, and a thinner white thread stretches between the two pieces like a rubber band's core.
• If the strand simply snaps in two with nothing inside, it is not usnea. Wikipedia notes that Alectoria branches snap off cleanly while usnea branches are somewhat elastic.

Take a close-up photo of the exposed cord; it is the evidence that confirms the ID.

• Witch's hair lichen (Alectoria sarmentosa): pale grayish-green to yellowish-green hanging mats 10 to 30 cm long, with small white raised ridges, in mature, wet forests with clean air from Alaska to northern California and in the Appalachians. It lacks the central cord (Wikipedia).
• Horsehair lichens (Bryoria): slender hair-like strands hanging from conifers, dark brown to pale grayish-brown or gray, without the central cord (Wikipedia). Color alone usually rules these out.
• Strap lichens (Ramalina): greenish lichens with flattened, strap-like branches (Wikipedia). Usnea branches are round in cross-section.
• Oakmoss (Evernia prunastri): flat branches 1 to 5 mm wide that fork like antlers, green above and slightly paler below, soft when dry and rubbery when wet, mostly on oak (Wikipedia).
• Spanish moss (Tillandsia usneoides): not a lichen at all but a flowering plant in the pineapple family; see the next section.

Of the top-ranking pages, none lists all five with the feature that separates each one.

Spanish moss's scientific name, usneoides, means 'resembling Usnea', but it is a bromeliad — a flowering plant — and neither a moss nor a lichen (Wikipedia, Spanish moss). Three checks settle it:

• Leaves: Spanish moss has real leaves, thin and curly, 2 to 6 cm long and about 1 mm wide, covered in gray scales. Usnea has no leaves, only branching strands.
• Flowers: Spanish moss produces small red-pink flowers. Usnea never flowers; at most it shows disc-like fruiting bodies (Woodland Trust).
• Stretch test: Spanish moss has no elastic white cord.

Range helps too. In North America, Spanish moss grows in a band along the Gulf of Mexico and the southern Atlantic coast, and it can hang up to 6 m (Wikipedia). If you are in Britain, the Pacific Northwest or New England, a hanging gray-green beard is a lichen, not Spanish moss.

Usnea grows on the bark and twigs of trees in both hemispheres, with the greatest diversity in tropical and subtropical regions (Wikipedia). The Woodland Trust says beard lichens only grow in woodlands with clear air and were lost from many parts of the UK during the era of sulfur dioxide pollution; in Britain, Usnea subfloridana is the most widespread and is now returning to London and the Midlands.

Wikipedia's Lichen article adds the general rule: where sulfur dioxide pollution is severe there may be no lichens at all, and in clean air shrubby, hairy and leafy lichens become abundant. Finding usnea on a branch is a sign the local air is relatively clean.

Do not eat usnea or take usnea products because of an identification from a photo or a web page. Usnea contains usnic acid, and Wikipedia's Usnic acid article reports that daily oral intake of 300 to 1,350 mg over several weeks has led to severe liver toxicity in a number of people. The US FDA issued a warning on November 20, 2001, about the weight-loss supplement Lipokinetix, which contained sodium usnate, after reports of liver injury and liver failure; the product also contained other active ingredients. Wikipedia's Usnea article also summarizes US National Toxicology Program studies that found liver damage in rats and liver toxicity in mice at higher exposures.

Lichens have been listed as emergency food in some traditions, but that is not a reason to try it. If someone has swallowed usnea or a usnea supplement and feels unwell, or has yellowing skin, dark urine or stomach pain after taking one, contact poison control or a doctor promptly. Anyone considering usnea for any health purpose should talk to a doctor first.

The Woodland Trust notes that beard lichens contain usnic acid, an antibacterial and antifungal compound, and were traditionally used to treat wounds and to make dyes in orange, yellow, green, blue and purple. Wikipedia's Usnea article lists antimicrobial uses, textile dyes, fire starting and emergency food.

A traditional use is not proof that a product is safe or that it works. Because of the liver injury reports above, get medical advice before using any usnea tincture, capsule or tea, and do not treat a wound with it in place of proper care.

Lichens often grow less than a millimeter a year (Wikipedia, Lichen), and the Woodland Trust describes beard lichens as microhabitat, shelter and food for small invertebrates that in turn feed birds. A tuft you pull off a living branch can take many years to replace.

If you want a specimen for identification, pick up strands from branches that have already fallen after a storm, take only a little, and photograph living tufts instead of removing them. Check local rules first: collecting is not allowed in many parks and reserves.

NatureLens identifies lichens, mosses and plants from a photo, with free scans every day. For a beard lichen, photograph the whole tuft on its branch, then a close-up of a strand pulled apart to show the cord (or the lack of one). The app's suggestion plus the stretch test is a much stronger ID than either alone. For look-alike safety in general, see avoid toxic look-alikes.

Research and drafting for this page used AI assistance. Every measurement, date and claim was then checked against the sources listed below, which were opened and read on 2026-09-25. Where two sources give different numbers, both are shown with the source named.