Lycopodiopsida

Lycopodiopsida Temporal range: Devonian–Recent PreꞒ Ꞓ O S D C P T J K Pg N
Palhinhaea cernua with close-up of branch
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Clade:	Lycophytes
Class:	Lycopodiopsida Bartl.
Orders
Isoetales (quillworts) Lycopodiales (clubmosses, firmosses) Selaginellales (spikemosses) †Lepidodendrales (arborecent lycophytes/scale trees)
Synonyms
See Table 1.

Lycopodiopsida is a class of vascular plants also known as lycopods or lycophytes. Members of the class are also called clubmosses, firmosses, spikemosses and quillworts. They have dichotomously branching stems bearing simple leaves called microphylls and reproduce by means of spores borne in sporangia on the sides of the stems at the bases of the leaves. Although living species are small, during the Carboniferous, extinct tree-like forms (Lepidodendrales) formed huge forests that dominated the landscape and contributed to coal deposits.

The nomenclature and classification of plants with microphylls varies substantially among authors. A consensus classification for extant (living) species was produced in 2016 by the Pteridophyte Phylogeny Group (PPG I), which places them all in the class Lycopodiopsida, which includes the classes Isoetopsida and Selaginellopsida used in other systems. (See Table 2.) Alternative classification systems have used ranks from division (phylum) to subclass. In the PPG I system, the class is divided into three orders, Lycopodiales, Isoetales and Selaginellales.