Thallus Formation of the Cyanobacterial Lichen Peltigera didactyla from Soredia under Laboratory Conditions

Abstract Formation of mature thalli with soredia occurred within an average cultivation time of 5 to 6 months. The size and growth form of the thalli (mussel‐shaped and branched type) were dependent upon the number of the soredia which were involved in the thallus‐forming process. Not only soredia amalgamated forming a soredia‐field, but also whole lobes fused during development. Contamination problems with soredia were partially overcome by using soredia from cultivated thalli.