A. brodoana A. gowardii A. imshaugii A. lata A. mexicana A. ochroleuca A. ochroleucoides A. sarmentosa A. sorediosa A. spiculatosa Alectoria is a genus of fruticose lichens belonging to the family Parmeliaceae.

[3] During the late 18th century, botanists such as Georg Franz Hoffmann (1796) began distinguishing filamentous lichens as a separate taxonomic group, though they did not establish a dedicated genus for them.

[4] Acharius, a student of Linnaeus and one of the pioneers of lichenology, initially placed species now assigned to Alectoria within Parmelia, grouping them under the section Tricharia in his 1803 work Methodus Lichenum.

[3] However, as he continued studying the group, he recognised the need for a separate genus and formally established Alectoria in 1809,[2] distinguishing it from Parmelia based on its slender, branching thallus structure.

[6] In the mid-19th century, William Nylander (1860) and James Crombie (1876) contributed to the understanding of Alectoria, using both morphological features and chemical analyses to differentiate it from closely related genera.

[9][10] These revisions provided a stable framework for the genus, which remains distinguished by its fruticose (shrub-like), filamentous thallus, lack of cyphellae (small pore-like structures), and its characteristic production of usnic acid and other lichen compounds.

[12] A distinctive feature of Alectoria is the presence of white, spindle-shaped structures called pseudocyphellae, which appear as small pores or marks on the surface.