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Placynthium tantaleum (Hepp) Hue
Family: Placynthiaceae
[Biatora corallinoides var. tantaleum Hepp,  more]
Placynthium tantaleum image

Global occurrence: Eurasia – Europe | Americas – North America (incl Mexico) | Arctic. Substrate: bark, cork, plant surface – trunks, branches, twigs | rock, stones, pebbles – unspecified.  Life habit: lichenized (mutualistic with algal photobionts).  Thallus: crustose (crustaceous) – episubstratal – unspecified; granular, granulose, granulate | compartimentized – areolate, squamulate; [th] upper surface: black(ish) | blue(ish) black | brown(ish) black | grey(ish) white; [th marginal and upper surface] specific structures: absent; [th] morphol substructures (eg areoles, lobes, branches) width [mm]: (min) 2.0; [th] morphol substructures (eg areoles, lobes, branches) upper surface: granulose, granular.  Ascomata: absent | present; ascoma: apothecial, apothecioid – hymenial; [ascm, if apoth] disc, mazaedium: black(ish) | brown(ish) (if pale: fawn, tan; if mid: cinnamon); [ascm] paraphyses/-oids: present.  Asci: lecanoralean; [asc] tholus: thickened; [asc] tholus amyloidity (iodine reaction): present; [asc] tholus amyloidity pattern: with amyloid tube, ring (= Collema-, Micarea-, Porpidia-, Psora-types etc).  Ascospores: (median) 8.0; [asp] shape: broadly ellipsoidal | ovoid, ovate; [asp] length [µm]: (min) 9.0 (low) 10.0 (high) 13.0 (max) 20.0; [asp] width [µm]: (min) 5.5 (low) 6.0 (high) 8.0 (max) 9.0; [asp] septa: absent – spore lumen unilocular, monolocular | present; transversely septate; [asp] transversal septa: (median) 1.0; [asp] pigmentation: hyaline, colourless.  Secondary metabolites: absent.  Primary photobiont: present, cyanobacterial.  Secondary photobionts (eg in cephalodia): absent.