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Arthonia phaeobaea (Norman) Norman
Family: Arthoniaceae
[Allarthonia phaeobaea (Norman) Zahlbr.,  more]
Arthonia phaeobaea image
Stephen Sharnoff  

Global occurrence: Eurasia – Europe | Americas – North America (incl Mexico) | Arctic.  Substrate: rock – siliceous, siliciferous, acidic | rock, stones, pebbles – unspecified. Life habit: lichenized (mutualistic with algal photobionts).  Thallus: crustose (crustaceous) – episubstratal – unspecified; [th] upper surface: brown(ish) (if pale: fawn, tan; if mid: cinnamon) | red(dish) brown (if pale: orange brown); [th marginal and upper surface] specific structures: absent; [th] morphol substructures (eg areoles, lobes, branches) upper surface: smooth, plane | cracked, fissured, fractured, rimulose, subrimose.  Ascomata: absent | present; ascoma: apothecial, apothecioid – hymenial; ascoma [mm]: (low) 0.16 (high) 0.3; [ascm, if apoth] disc, mazaedium: plane, flat, flattened, expanded | subconvex, slightly convex; [ascm, if apoth] disc, mazaedium: black(ish) | brown(ish) black; [ascm, if apoth] disc, mazaedium: epruinose | pruinose; [ascm, if apoth] subhymenial layers, hypothecium; [if perith] basal excipulum: brown(ish) (if pale: fawn, tan; if mid: cinnamon) | hyaline, colourless; [ascm] paraphyses/-oids: present; [ascm] epihymenium, epithecium: red(dish) brown (pale: orange brown).  Asci: fissitunicate – bitunicate; [asc] tholus: thickened; [asc] tholus amyloidity (iodine reaction): absent | present; [asc] tholus amyloidity pattern: with amyloid tube, ring (= Collema-, Micarea-, Porpidia-, Psora-types etc).  Ascospores: (median) 8.0; [asp] shape: oblong, oblong-obtuse; [asp] length [µm]: (low) 17.0 (high) 30.0; [asp] width [µm]: (low) 5.0 (high) 7.0; [asp] septa: present, transversely septate; [asp] transversal septa: (low) 3.0 (high) 5.0; [asp] pigmentation: hyaline, colourless; [asp] perispore, epispore: thick, distincly halonate.  Conidiomata: absent | present.  Conidia: oblong, oblong-obtuse; [co] length [µm]: (low) 4.0 (high) 5.5.  Secondary metabolites: absent.  Primary photobiont: present, chlorophytaceous – trebouxiaceous, chlorococcoid.  Secondary photobionts (eg in cephalodia): absent.