Life habit: lichenized (mutualistic with algal photobionts) thallus: crustose (crustaceous) – endosubstratal, inconspicuous, immersed [th] upper surface: grey(ish) | red(dish) brown (if pale: orange brown) [th marginal and upper surface] specific structures: absent ascomata: absent | present ascoma: apothecial, apothecioid – hymenial ascoma: immersed, innate [ascm, if apoth] disc, mazaedium: black(ish) [ascm] paraphyses/-oids: present asci: lecanoralean [asc] tholus: thickened [asc] tholus amyloidity (iodine reaction): absent ascospores: (median) 8.0 [asp] shape: globose, spherical | subglobose, subspherical | broadly ellipsoidal | ellipsoidal [asp] length [µm]: (low) 7.0 (high) 14.0 [asp] width [µm]: (low) 6.0 (high) 10.0 [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 – trentepohliaceous, trentepohlioid.

substrate: rock – calcareous, calciferous, basic.

Thallus pale ochraceous or ashy gray, cracky-areolate, sometimes appearing radiate, to 0.5 mm thick. Apothecia raised on thallus, with prominent lecanorine margin, the margin smooth, regular; proper exciple distinct, paraplecten-chymatous. widening to the surface; hypothecium 35 μm, grayish; hymenium 100-110 μm, upper part bluish-green; paraphyses indistinct in water, more visible in KOH, cylindrical, 1.7-2.0 μm, branched, septate; spores 10-14 x 7-8 μm. Pycnidia rare; conidia 6-7 x 1 μm, cylindrical.

Reactions: upper part of exciple and hymenium HNO, + violet, 1+ blue or brownish yellow.

This species grows on river banks and irrigated rocks. It is known from northeastern Greenland (Lynge 1940, sin. loc.), Novaya Zemlya, and Sweden. A specimen in WIS collcctcd by Mason E. Hale at Pond Inlet. Baffin Island, Northwest Territories. and labeled "cf. spitsbtrgensis" by Magnusson, seems to fit this species better. It was compared with the type of that at Oslo and has a light, not dark margin, slender paraphyses, is not capitate and is chinky rather than arcolatc. Another specimen from Devon Island, Schulten 16, was originally determined I. schismatopsis.

Thallus poorly developed, thin, smooth or chinky around the apothecia, dirty yellow, sometimes reduced to a thin film around the apothecia. Apothecia 0.1-0.12 mm broad, immersed in thallus or substratum; upper part of proper exciple dark brown-green, lower part hyaline; disk concave, black; epithecium and upper hymenium dark blue-green, fading below; paraphyses in much gelatin, little branched, thickening toward tips to 3-3.5 μm; spores 6-8, biseriate, ellipsoid, 8-13 x 6-8 μm.

Reactions: blue parts of exciple and hymenium turn violet with HNO.

This species grows on calcareous substrata. It is known from Novaya Zemlya, Lapland, and near Wainright, Alaska.