For the most part we all know that lichens are actually two organisms coexisting as one in a relationship that is known to be symbiotic. That is one organism relies on the other for the necessities of life and the other vice versa. It was suggested by Simon Schwendener, a German, that the relationship was one of controlled parasitism. Where the fungi, being of the class Ascomycetes, which thrives upon the labors of another, actually enslaves the algal cells and keeps them imprisoned in the fungal filaments to fulfill the requirements for its existence but yet provides for the algae a degree of protection and the ability to thrive along with the fungi in areas where the algae would not normally be able to survive without the fungi. This statement may be, to some, contradictory because I have given both the reason for a symbiotic union and for one of controlled parasitism. I find myself leaning more towards the suggestion given by Schwendener. I have always been one to challenge the norm. However, many other questions come to mind in considering the lichen. For example, where did the algae that the fungi has compelled into its service originate? Was it carried into reach by insects, birds, or some other animals or did it just ride in on the wind and happen to settle within the proximity of the fungi? Why is it only one or maybe two species of algae in particular or only one or maybe two kinds of cyanobacterium? Why not some other forms of algae or blue-green algae (cyanobacteria)? I am not a botanist nor a lichenologist by any means but only a hillbilly with a couple of microscopes and a lot of time on his hands to go prying around in the affairs of mother nature. However I do sort of fancy myself as being somewhat of a naturalist. The answer to some or all of my questions maybe quite obvious to some but then again they seem to escape me. Thoughts anyone?
Some of these questions are addressed in Brodo's Lichens of North America - the short answer to the questions is that any answers one comes up with remain speculation.
Daniel replied: Unfortunately that seems to be the case in a lot of organisms. I was just fishing for opinions and educated guesses I suppose. Food for thought you might say. However the opinion of Schwendener as to the relationship being one of contolled parasitism is intriuging and the more I consider it the more I am convinced, or maybe it could be that I am wanting to be convinced, that his observations are correct.
