General:
Minute to small stratified foliose or occasionally fruticose lichens, corticate above and below, sorediate or isidiate or not, lobes closely appressed to loosely attached or semi-erect, short to more often elongate or elongatelinear, averaging to 0.3–1 (–2) mm wide, thin or somewhat thick. Upper surface orange or orangish, K+ purple. Lower surface pale, often whitish, often bearing scattered, short, simple rhizines. Medulla white. Photobiont green Apothecia located over upper surface, disc orange; spores 2-celled, ellipsoid, colourless, 8 per ascus. Over base-rich rock and bark, occasionally over bone.

Notes: Xanthoria is primarily a temperate genus consisting of approximately 15 species worldwide. Ten are reported for North America and six for B.C. The western Xanthoriae are in need of taxonomic revision; therefore the following account is tentative, pending further study. Chemistry is of little taxonomic value in this genus and is omitted.

Species description:
Soredia and/or isidia present AND Isidia and/or soredia located mostly along lobe margins and/or lobe tips, sometimes also developing on lower surface AND Lobes proportionately rather short and broad, sorediate, soredia clustered along lobe margins and especially the lower surface; rhizines present; over bark

Comments:
See notes under X. candelaria and X. sp. 1.

Source:  Lichens of British Columbia

If more than one illustration is available for a species (e.g., separate illustrations were provided for two subspecies) then links to the separate images will be provided below. Note that individual subspecies or varietal illustrations are not always available.

Illustration By:  Trevor Goward