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Rinodina exigua (Ach.) Gray
Family: Physciaceae
[Berengeria exigua (Ach.) Trevis.,  more]
Rinodina exigua image

Global occurrence: Africa (incl Madagascar) | Eurasia – Europe | Americas – North America (incl Mexico) | Arctic.  Substrate: wood – dead, living | bark, cork, plant surface – trunks, branches, twigs.  Life habit: lichenized (mutualistic with algal photobionts). Thallus: crustose (crustaceous) – episubstratal – unspecified; continuous, diffuse, effuse | cracked, fissured, fractured, rimose; [th] upper surface: grey(ish) | white(ish) | white(ish) brown (beige); [th upper surface]: epruinose; [th marginal and upper surface] specific structures: absent; [th] morphol substructures (eg areoles, lobes, branches) upper surface: smooth, plane | granulose, granular.  Ascomata: absent | present; ascoma: apothecial, apothecioid – hymenial; ascoma [mm]: (low) 0.3 (high) 0.6 (max) 0.7; ascoma: immersed, innate | subsessile, subimmersed, adnate, semi-immersed, emergent | 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: grey(ish) | white(ish) | white(ish) brown (beige); [ascm, if apoth] margin excipular photobionts: absent | present; [ascm, if apoth] subhymenial layers, hypothecium; [if perith] basal excipulum: hyaline, colourless; [ascm] paraphyses/-oids: present; [ascm] epihymenium, epithecium: brown(ish) (if pale: fawn, tan; if mid: cinnamon) | grey(ish) brown | yellow(ish) brown | red(dish) brown (pale: orange brown).  Asci: lecanoralean; [asc] tholus: thickened; [asc] tholus amyloidity (iodine reaction): present; [asc] tholus amyloidity pattern: amyloid with widening axial body towards the apex (= Lecanora-, Parmelia-, Rinodina-types etc).  Ascospores: (median) 8.0; [asp] shape: ellipsoidal; [asp] length [µm]: (low) 15.0 (high) 21.0 (max) 23.0; [asp] width [µm]: (low) 7.0 (high) 9.0 (max) 10.0; [asp] septa: present; [asp] septa: transversely septate; [asp] transversal septa: (median) 1.0; [asp] pigmentation: pale brown | medium brown, brownish | dark brown; [asp] perispore, epispore: ornamented, rough, warted, striate, cracked.  Secondary metabolites: present, atranorin.  Primary photobiont: present, chlorophytaceous – trebouxiaceous, chlorococcoid.  Secondary photobionts (eg in cephalodia): absent.