Usnea on the brach

Usnea on the brach

Usnea
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Usnea
Usnea australis.jpg
Usnea australis
Scientific classificatione
Kingdom: Fungi
Division: Ascomycota
Class: Lecanoromycetes
Order: Lecanorales
Family: Parmeliaceae
Genus: Usnea
Dill. ex. Adans. (1763)
Type species
Usnea florida
(L.) F.H.Wigg. (1780)
Species
See text

Usnea is a genus of mostly pale grayish-green fruticose lichens that grow like leafless mini-shrubs or tassels anchored on bark or twigs.[1]:203 The genus is in the family Parmeliaceae. It grows all over the world.

Members of the genus are commonly called old man's beard, or beard lichen.[1]:203 It resembles Evernia, which is also called tree moss.[2]

Like other lichens it is a symbiosis of a fungus and an alga. In Usnea, the fungus belongs to the division Ascomycota, while the alga is a member of the division Chlorophyta.

Members of the genus are similar to those of the genus Alectoria.[1]:148 A distinguishing test is that the branches of Usnea are somewhat elastic, but the branches of Alectoria snap cleanly off.