thumb|upright=1.6|right|Bipartite and tripartite cyanolichens. (A) In the bipartite cyanolichen [[Peltigera scabrosa the cyanobacterial symbiont (Nostoc) forms a continuous layer just below the upper cortex of the lichen thallus. (B) Nephroma bellum is another example of bipartite cyanolichens. (C) In the tripartite cyanolichen Peltigera aphthosa the Nostoc symbiont is restricted to wart-like cephalodia (shown magnified) on the upper surface of the thallus, while the green algal symbiont (Coccomyxa) forms the photobiont layer. (D) Nephroma arcticum is another example of tripartite cyanolichens. The large cephalodia of this species are internal, but clearly visible through the upper cortex of the hydrated thallus.

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