Sphagnum exhibit a high degree of genetic and phenotypic variation in structure at all levels within their organization including (a) across hummock–hollow microhabitats, (b) within colonies, (c) within shoots that show variation in branch distribution and density, (d) on branches, (e) in leaf size and shape, and (f) in the size and arrangement of photosynthetic and hyaline cells. Variation at each of these organizational levels affects plant function (drawing by S. Webb; from Rice, SK 2009. Bryophytes. In Likens, GE (ed.), Encyclopedia of Inland Waters. Elsevier, Oxford, UK).
