Abstract
The total N, P, Mg, Ca, K and Na contents were investigated in the thalli of several lichen species occurring on various trees, and in the bark and bark extracts from these trees. pH of the bark extracts was also determined. Wide differences were found in the content of the elements in point in the thalli of various lichen species on Acer platanoides and on the thalli of the same species on other trees. No relation was detected between the chemical composition of the bark and that of the lichen thalli occurring on it.