Some lichenised fungi are capable of associating with both cyanobacteria and algae as photosynthetic partners. In some cases the appearance of the lichen changes very dramatically depending on which photobiont is present.
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| Ricasolia virens - cyanomorph |
For example, here is Ricasolia virens - a small, bushy, cushion-forming jelly lichen. A cyanobacterium is the photobiont here.
But... This is also Ricasolia virens - a large, strikingly green, foliose lichen. This one has an alga as the photobiont:
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| Ricasolia virens - chloromorph |
You can call the cyanobacterium containing lichen a cyanomorph and the alga containing lichen a chloromorph.
Sometimes you will find a lichen with both photobionts on the same thallus - this can be called a photosymbiodeme. Here is a Ricasolia virens photosymbiodeme:
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| Ricasolia virens - photosymbiodeme |
Related phenomena occur with Sticta canariensis and Ricasolia amplissima.
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| Sticta canariensis - photosymbiodeme |
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| Ricasolia amplissima - photosymbiodeme |
A slight complication: the word cephalodium can also be used to describe a lichen with algae and cyanobacteria both present, but it only allows for cases where the cyanobacteria are kept in small, subsidiary structures within or budding off of a primary chloromorphic thallus.
You can read much more about Ricasolia virens and its forms in this 2016 paper:
The cyanomorph of Ricasolia virens comb. nov. (Lobariaceae, lichenized Ascomycetes)
By
Tønsberg, Blom, Goffinet, Holtan-Hartwig & Lindblom
https://doi.org/10.5962/p.386096
As the Ricasolia virens cyanomorph is seldom reported, here is an image matrix comparing it with Scytinium lichenoides (left) and Ricasolia amplissima cephalodia (right).
Row 1: overall shape; Row 2: surface texture; Row 3: cross section; Row 4: micrograph of cortex cells
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| Scytinium lichenoides - Ricasolia virens - Ricasolia amplissima |
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