...and since there is apparently such a thing as algicolous fungi, leaving on and in (maybe only marine) algae, and not always causing detectable disease;
we now have a situation where A&B (lichen) is more than A&B (algicolous fungi living on algae) in most cases, and the reverse is true for some special cases (like water content).
I get that A&B can be more than A+B, but I don’t think we can get away with having the same thing be A&B or A+B whenever we feel like it and still be doing science.
...and since there is apparently such a thing as algicolous fungi, leaving on and in (maybe only marine) algae, and not always causing detectable disease;
we now have a situation where A&B (lichen) is more than A&B (algicolous fungi living on algae) in most cases, and the reverse is true for some special cases (like water content).
I get that A&B can be more than A+B, but I don’t think we can get away with having the same thing be A&B or A+B whenever we feel like it and still be doing science.