Sphagnum is an amazing little plant. It is unique morphologically with its terminal tuft of branches (capitulum) and clustered branches along the main stem. These latter branches are dimorphic: spreading away from the main stem (divergent) and hanging down along the main stem (pendent).
Microscopically it is a treat. The leaves have large dead hyaline cells patterned with pores and wall thickenings (fibrils) surrounded by photosynthetic cells. Differences in distribution and structures help with identification (see key). There are approximately 250 species, but lucky for us we have only 20 or so locally.
Ecologically, this moss generates its own ecosystem. It is the foundation on which bogs are built. In fact you could say that other vegetation is epiphytic on Sphagnum. It not only thrives in this acidic environment, but contributes to acidity through its cation exchange system. Bogs with their unique flora make them a fascinating ecosystem to explore.
It is easy to see why Sphagnum for many becomes an obsession!
Sphagnum until recently was the only genus in the Sphagnopsida. The discovery in Tasmania of a very unusual related plant, named Ambuchanania, resulted in the addition of a new family Ambuchananiaceae. Phylogenetic studies using molecular techniques have revealed interesting relationships and have prompted re-evaluation of the taxonomy and the addition of two new genera (new families) and families () (Shaw, 2010)