Mouldering in a Gloomy Spot

 Fencepost of the Week #253

 

 

 

 

Roll-up

 Fencepost of the Week #252

 This entire fence has been pulled out of the ground and rolled up. It's still providing fertile surfaces for some nice lichens and mosses, though.

 

Grizzled and Cracked

 Fencepost of the Week #251

 

 

Cavernous Crater at Dusk

 Fencepost of the Week #250

 

 

Ricasolia virens - Cyanomorph, Chloromorph and Photosymbiodeme

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.

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:

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:

Ricasolia virens - photosymbiodeme

Related phenomena occur with Sticta canariensis and Ricasolia amplissima.

Sticta canariensis - photosymbiodeme

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

Diversity in Black and Green

 Fencepost of the Week #249

 A beguiling assemblage of lichens on this post betwixt field and forest.

 

Crowned in Sticta

 Fencepost of the Week #248

 Sticta sylvatica thriving in a damp, shady corner of the paddock.