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 saturated organic layers could actually rupture, spilling large volumes of mud and organic debris to surrounding fields, thus enabling a bed for further spatial expansion of the entire bog. Ultimately the colour of the moss waters became blood red in colour, from the successive organic decay and stagnation. Only in times associated with cattle grazing and significant human presence (probably the late Iron Age), would this process reverse and the bog reduce in size. A wide variety of sphagnum, sedges, rushes and other characteristic bog species inhabit Portlethen Moss. Sometimes insectivorous plants reside in mosses, since the soils are generally