There are three words that you are unlikely to see together in the same sentence ever again. What is my excuse here? There is a well-known relationship between sunshine and moss or lichen growth, but there are subtler, more interesting ones as well. I have lost count of the number of people who have confidently told me that moss only grows on the north side of trees and buildings. I have dealt with that partial myth elsewhere, but here I want to explore a rarely-noted trend.
In England and large parts of northern Europe mosses and lichens will often grow on the south side of trees and buildings, but they will nearly always display differences to nearby brethren growing on the north side. The crucial thing to remember is that we are dealing with trends and patterns when observing nature, avoiding rules wherever possible. The navigator who tries to…
