Moss among three divisions: Bryophyta, Marchantiophyta and Anthocerotophyta. The current circumscription of Bryophyta includes only the mosses. The mosses, now division Bryophyta (Bryophyta sensu stricto), are divided into eight classes: Six of the eight classes contain only one or two genera each. Polytrichopsida includes 23 genera, and Bryopsida includes the majority of moss diversity with over 95% of moss species belonging to this class. The Sphagnopsida, the peat-mosses, comprise the two living genera "Ambuchanania" and "Sphagnum", as well as fossil taxa. However, the genus "Sphagnum" is a diverse, widespread, and economically important one. These large mosses form extensive acidic bogs in
Portlethen Moss lower elevations in every direction. Due to the high winds, moderate precipitation and cool temperatures that generally prevail, conditions are favourable for formation of an acid bog, since water stagnates, but eventually evaporates with ensuing acidity enhancement of decaying organic matter. There was virtually no drainage outlet in prehistoric times, and little drainage even in modern times. Many coastal mosses were initiated by the process of glaciation, which sheared rock formations to a generally level terrain, while also gouging moderate sized craters that would pond. This description fits the fundamental situation of Portlethen Moss, where sphagnum would have flourished over