Slideshow image
Rhizocarpon concentricum (Davies) Beltram.
Family: Rhizocarpaceae
[Buellia concentrica (Davies) H. Olivier,  more]
Rhizocarpon concentricum image
Life habit: lichenized (mutualistic with algal photobionts) thallus: crustose (crustaceous) – episubstratal – unspecified thallus: continuous, diffuse, effuse | cracked, fissured, fractured, rimose | compartimentized – areolate, squamulate [th] upper surface: grey(ish) | white(ish) grey [th marginal and upper surface] specific structures: absent [th] morphol substructures (eg areoles, lobes, branches) width [mm]: (min) 0.5 [th] morphol substructures (eg areoles, squamules): contiguous, coherent (throughout the thallus) ascomata: absent | present ascoma: apothecial, apothecioid – hymenial ascoma [mm]: (min) 1.0 ascoma: sessile, superficial [ascm, if apoth] disc, mazaedium: plane, flat, flattened, expanded [ascm, if apoth] disc, mazaedium: black(ish) [ascm, if apoth] disc, mazaedium: epruinose [ascm, if apoth] margin surface; [if perith] periostiolar area, ostiole, involucrellum: black(ish) [ascm, if apoth] margin excipular photobionts: absent [ascm, if apoth] subhymenial layers, hypothecium; [if perith] basal excipulum: brown(ish) (if pale: fawn, tan; if mid: cinnamon) [ascm] paraphyses/-oids: present [ascm] epihymenium, epithecium: green(ish) brown (olive brown) asci: lecanoralean [asc] tholus: thickened [asc] tholus amyloidity (iodine reaction): present [asc] tholus amyloidity pattern: with amyloid cap (= Icmadophila-, Lecidea-, Pertusaria-types etc) ascospores: (median) 8.0 [asp] shape: ellipsoidal [asp] length [µm]: (low) 20.0 (high) 50.0 [asp] width [µm]: (low) 13.0 (high) 24.0 [asp] septa: present [asp] septa: muriformly septate – muriform, submuriform [asp] pigmentation: hyaline, colourless | dark brown [asp] perispore, epispore: thick, distincly halonate secondary metabolites: present secondary metabolites: stictic acid primary photobiont: present secondary photobionts (eg in cephalodia): absent primary photobiont: chlorophytaceous – trebouxiaceous, chlorococcoid.

substrate: rock – siliceous, siliciferous, acidic | rock – calcareous, calciferous, basic.