One very large patch in a semi-clearing in Lophozonia menziesii forest.
Dendrolycopodium obscurum. Rock Creek Park, Washington, DC, USA
Lycopodiopsida is a class of plants often loosely grouped as the fern allies. Traditionally the group included not only the clubmosses and firmosses, but also the spikemosses (Selaginella and relatives) and the quillworts (Isoetes and relatives). However, the latter are now usually separated off into a separate class, Isoetopsida.