Slideshow image
Thelidium minutulum Korber
Family: Verrucariaceae
[Arthopyrenia mesotropa (Nyl.) Arnold,  more]
Thelidium minutulum image
Troy McMullin  
Life habit: lichenized (mutualistic with algal photobionts) thallus: crustose (crustaceous) – episubstratal – unspecified thallus: continuous, diffuse, effuse | cracked, fissured, fractured, rimose [th] upper surface: brown(ish) (if pale: fawn, tan; if mid: cinnamon) | green(ish) grey | brown(ish) grey | grey(ish) green [th marginal and upper surface] specific structures: absent ascomata: absent | present ascoma: perithecial, perithecioid – hymenial ascoma [mm]: (min) 0.085 (low) 0.1 (high) 0.26 (max) 0.4 ascoma: subsessile, subimmersed, adnate, semi-immersed, emergent | sessile, superficial [ascm, if apoth] margin surface; [if perith] periostiolar area, ostiole, involucrellum: brown(ish) (if pale: fawn, tan; if mid: cinnamon) | brown(ish) black [ascm, if apoth] margin excipular photobionts: absent [ascm] paraphyses/-oids: absent asci: fissitunicate – bitunicate [asc] tholus: thickened [asc] tholus amyloidity (iodine reaction): absent ascospores: (median) 8.0 [asp] shape: ellipsoidal [asp] length [µm]: (min) 12.0 (low) 19.0(median) 22.0 (high) 25.0 (max) 30.5 [asp] width [µm]: (min) 5.0 (low) 8.5(median) 9.6 (high) 10.5 (max) 13.0 [asp] septa: present [asp] septa: transversely septate [asp] transversal septa: (median) 1.0 [asp] pigmentation: hyaline, colourless [asp] perispore, epispore: not apparent secondary metabolites: absent primary photobiont: present secondary photobionts (eg in cephalodia): absent primary photobiont: chlorophytaceous – trebouxiaceous, chlorococcoid.

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