Lycopodiopsida

Lycopodiopsida is a class of vascular plants also known as lycopsids, lycopods, or lycophytes, whose members include the clubmosses, firmosses, spikemosses, and quillworts. They have stems that branch by repeated forking and bear simple leaves called microphylls, reproducing by spores held in sporangia at the base of the leaves. Although living species are small, extinct tree sized relatives called Lepidodendrales formed vast Carboniferous forests that contributed heavily to coal deposits worldwide.