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Dermatocarpon rivulorum (Arnold) Dalla Torre & Sarnth.
Family: Verrucariaceae
[Endocarpon rivulorum Arnold,  more]
Dermatocarpon rivulorum image
Stephen Sharnoff  
Life habit: lichenized (mutualistic with algal photobionts) thallus: peltate, umbilicate thallus: continuous, diffuse, effuse [th] upper surface: grey(ish) brown | green(ish) brown (olive brown) [th upper surface]: epruinose | pruinose [th upper surface] pruina: scarce, sparse, fine [th marginal and upper surface] specific structures: absent [th] morphol substructures (eg areoles, lobes, branches) width [mm]: (low) 15.0 (high) 35.0 [th] morphol substructures (eg areoles, squamules): contiguous, coherent (throughout the thallus) [th] lower surface: brown(ish) (if pale: fawn, tan; if mid: cinnamon) [th lower surface] specific structures: absent [th] medulla amyloidity: absent ascomata: absent | present ascoma: perithecial, perithecioid – hymenial [ascm] paraphyses/-oids: absent asci: fissitunicate – verrucarialean [asc] tholus: thickened [asc] tholus amyloidity (iodine reaction): absent ascospores: (median) 8.0 [asp] length [µm]: (low) 13.0 (high) 21.0 (max) 24.0 [asp] width [µm]: (min) 6.0 (low) 6.5 (high) 8.5 (max) 9.0 [asp] septa: absent – spore lumen unilocular, monolocular [asp] pigmentation: hyaline, colourless [asp] perispore, epispore: not apparent secondary metabolites: absent primary photobiont: present secondary photobionts (eg in cephalodia): absent primary photobiont: chlorophytaceous – trebouxiaceous, chlorococcoid.

substrate: rock – siliceous, siliciferous, acidic.