Classification of sphagna takes experience, and is sometimes impossible without the aid of a microscope. The following criteria are applied to distinguish between species:
Number of branches per fascicle
Number of pendent and spreading branches, and their degree of differentiation
Shape of branch leaves (squarrose, hooded, etc.)
Direction of stem leaves (upward, downward or horizontal)
Shape of the head
Size and prominence of the terminal bud
Secondary pigments
Shape and location of chlorocytes
Spiral fortification of hyalocytes
Number, size, and fortification of pores
Structure of hyalocyte cell walls (papillose or other ornamentations)