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Arthrorhaphis citrinella (Ach.) Poelt
Family: Arthrorhaphidaceae
[Arthrorhaphis flavovirescens (A. Massal.) Th. Fr.,  more]
Arthrorhaphis citrinella image
André Aptroot  

Global occurrence: Africa (incl Madagascar) | Antarctic – Antarctica | Oceania – Australasia | Eurasia – Europe | Americas – North America (incl Mexico) | Americas – South and Central America | Arctic.  Substrate: soil, clay, humus, turf, detritus, dead leaves | bryophytes – mosses, liverworts | lichens, lichenized fungi | rock – siliceous, siliciferous, acidic.  Life habit: lichenized (mutualistic with algal photobionts) | lichenicolous (in/on lichens).  Thallus: crustose (crustaceous) – episubstratal – unspecified, compartimentized – areolate, squamulate; [th] upper surface: green(ish) | yellow(ish) (if dull: buff) | yellow(ish) green; [th marginal and upper surface] specific structures: present; [th margin] cilia, cilioid structures: absent; [th upper surface] isidia, isidioid structures: absent; [th upper surface] soredia, soralia, soralioid structures: present; [th] morphol substructures (eg areoles, lobes, branches) upper surface: bullate. Ascomata: absent | present; ascoma: apothecial, apothecioid – hymenial; ascoma [mm]: (low) 0.2 (high) 0.6 (max) 1.0; [ascm, if apoth] disc, mazaedium: concave | plane, flat, flattened, expanded; [ascm, if apoth] disc, mazaedium: black(ish); [ascm, if apoth] subhymenial layers, hypothecium; [if perith] basal excipulum: hyaline, colourless; [ascm] paraphyses/-oids: present; [ascm] paraphyses/-oid cells width [µm]: (low) 1.5 (high) 2.5; [ascm] epihymenium, epithecium: green(ish). Asci: fissitunicate – bitunicate; [asc] tholus: not thickened | thickened; [asc] tholus amyloidity (iodine reaction): absent.  Ascospores: (median) 8.0; [asp] shape: fusiform | acicular (needle-shaped); [asp] length [µm]: (min) 36.0 (low) 47.0 (high) 80.0 (max) 100.0; [asp] width [µm]: (min) 2.0 (low) 3.0 (high) 5.5 (max) 6.0; [asp] septa: present, transversely septate; [asp] transversal septas: (min) 6.0 (low) 8.0 (high) 13.0 (max) 15.0; [asp] pigmentation: hyaline, colourless; [asp] perispore, epispore: not apparent.  Secondary metabolites: present, epanorin | rhizocarpic acid.  Primary photobiont: present; chlorophytaceous – trebouxiaceous, chlorococcoid.  Secondary photobionts (eg in cephalodia): absent.