Although it is impossible to be certain, according to Marion Rayner of the British Bryological Society, because of the grey green colours one study is probably of 'reindeer moss' which is actually a lichen (mosses are plants but lichens are two or three organisms - a fungus and alga or cyanobacteria living together in symbiotic relationship). The other study may be another lichen, pamelia saxatilis. These types of lichens can easily be found growing luxuriously in Scotland and in other areas of UK which have good air quality and high rainfall. WacWhirter was a precociously talented artist who had a picture exhibited at the Royal Scottish Academy when he was only 14. He made these studies when he was only 16, before he became the extensively travelled and accomplished Scottish landscape painter he is now known as.