Slideshow image
Acarospora umbilicata Bagl.
Family: Acarosporaceae
Acarospora umbilicata image

Global occurrence: Eurasia – Europe | Arctic.  Substrate: rock – siliceous, siliciferous, acidic.  Life habit:  lichenized (mutualistic with algal photobionts).  Thallus: crustose (crustaceous) – episubstratal – unspecified; compartimentized – areolate, squamulate; [th] upper surface: brown(ish) (if pale: fawn, tan; if mid: cinnamon) | black(ish) brown; [th upper surface]: epruinose | pruinose;  [th upper surface] pruina: scarce, sparse, fine | dense; [th marginal and upper surface] specific structures: absent; [th] morphol substructures (eg areoles, lobes, branches) width [mm]: (low) 0.5 (high) 3.0; [th] morphol substructures (eg areoles, lobes, branches) upper surface: subsquamulose.  Ascomata: absent | present; ascoma: apothecial, apothecioid – hymenial; ascoma [mm]: (median) 0.4; [ascm] paraphyses/-oids: present; [asc] tholus: thickened; [asc] tholus amyloidity (iodine reaction): absent.  Asci: lecanoralean.  Ascospores:  length [µm]: (low) 3.0 (high) 5.0; [asp] width [µm]: (low) 1.5 (high) 2.0; [asp] septa: absent – spore lumen unilocular, monolocular; [asp] pigmentation: hyaline, colourless; [asp] perispore, epispore: not apparent.  Secondary metabolites: present; gyrophoric acid.  Primary photobiont: present; chlorophytaceous – trebouxiaceous, chlorococcoid.  Secondary photobiont:  (eg in cephalodia): absent.