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Placopsis lambii Hertel & V. Wirth
Family: Trapeliaceae
Placopsis lambii image

Global occurrence: Oceania – Australasia | Eurasia – Europe | Americas – North America (incl Mexico) | Arctic. Substrate: rock – siliceous, siliciferous, acidic | rock, stones, pebbles – unspecified.  Life habit: lichenized (mutualistic with algal photobionts).  Thallus: crustose (crustaceous) – episubstratal – unspecified | placodioid-crustose, placodioid-foliose; cracked, fissured, fractured, rimose | compartimentized – areolate, squamulate; [th] upper surface: grey(ish) | yellow(ish) (if dull: buff) | brown(ish) (if pale: fawn, tan; if mid: cinnamon) | grey(ish) green | brown(ish) green (olivaceous, olive green) | white(ish) brown (beige) | green(ish) white | yellow(ish) white (ivory, off-white, cream-coloured); [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.  Ascomata: absent | present; ascoma: apothecial, apothecioid – hymenial; ascoma [mm]: (low) 0.2 (high) 1.0 (max) 1.5; ascoma: subsessile, subimmersed, adnate, semi-immersed, emergent | sessile, superficial; [ascm, if apoth] disc, mazaedium: plane, flat, flattened, expanded | subconcave, slightly concave; [ascm, if apoth] disc, mazaedium: red(dish) | white(ish) red (rose) | red(dish) white (pink); [ascm, if apoth] disc, mazaedium: epruinose | pruinose; [ascm, if apoth] disc, mazaedium pruina: scarce, sparse, fine; [ascm, if apoth] margin surface; [if perith] periostiolar area, ostiole, involucrellum: brown(ish) (if pale: fawn, tan; if mid: cinnamon) | yellow(ish) brown | red(dish) brown (if pale: orange brown); [ascm, if apoth] subhymenial layers, hypothecium; [if perith] basal excipulum: brown(ish) red (carneous); [ascm] paraphyses/-oids: present; [ascm] epihymenium, epithecium: green(ish) brown (olive brown).  Asci: lecanoralean; [asc] tholus: thickened; [asc] tholus amyloidity (iodine reaction): absent.  Ascospores: (median) 8.0; [asp] shape: broadly ellipsoidal; [asp] length [µm]: (low) 15.0 (high) 16.5 (max) 18.5; [asp] width [µm]: (low) 6.5 (high) 8.5; [asp] septa: absent – spore lumen unilocular, monolocular; [asp] pigmentation: hyaline, colourless; [asp] perispore, epispore: not apparent.  Conidiomata: absent | present.  Conidia: filiform, vermiform; [co] length [µm]: (low) 20.0 (high) 26.5.  Secondary metabolites: present, 5-O-methylhiascic acid | gyrophoric acid | hiascic acid.  Primary photobiont: present, chlorophytaceous – trebouxiaceous, chlorococcoid.  Secondary photobionts (eg in cephalodia): absent | present.