The Lycopodiaceae (class Lycopodiopsida, order Lycopodiales) are an old family of vascular plants, including all of the core clubmosses, comprising 16 accepted genera  and ca 400 known species. This family originated about 380 million years ago in the early Devonian, though the diversity within the family has been much more recent. They are non-flowering and do not produce seeds, and instead they produce spores. They develop oily, flammable spores, which are the most economically important aspects of these plants. The plants bear their spores on specialized structures at the apex of a shoot called a strobilus (plural: strobili); they resemble a tiny battle club, from which the common name derives. In Greek, Lyco- means "wolf," and podo means "foot," so Lycopodiaceae translated directly means "Wolf foot," which is another common name for this family due either to the resemblance of the roots or branch tips to a wolf's paw.
P.Beauv. ex Mirb. 1802
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The members of Lycopodiaceae are terrestrial or epiphytic in habit and are most prevalent in tropical mountain and alpine environments. Though Lycopodiaceae are most abundant in these regions, they are cosmopolitan, excluding arid environments.
Members of Lycopodiaceae share a common feature of having a microphyll, which is a “small leaf with a single vein, and not associated with a leaf gap in the central vascular system." In Lycopodiaceae, the microphylls often densely cover the stem in a linear, scale-like, or appressed fashion to the stem, and the leaves are either opposite or spirally arranged. The club mosses commonly grow to be 5-20 centimeters tall.
The core clubmosses are 16 accepted genera  and ca 400 known species. This classification is the most recent based on molecular data, though the systematics of this family are somewhat disputed. Genera Huperzia, Phlegmariurus and Phylloglossum, the species of which were generally included in a more broadly defined Lycopodium in older classifications, are now all placed in Huperzia although some authors prefer to separate these in the family Huperziaceae; they differ in producing spores in small lateral structures in the leaf axils. There is as yet no consensus on the recognition of Huperziaceae as a separate family; a more broadly defined Lycopodiaceae, including these genera, is still recognized in most general classifications.
The species within this family generally have chromosome counts of n=34. A notable exception are the species in Lycopodium subgenus Diphasiastrum, which have counts of n=23.
- The running clubmosses (Lycopodium subgenus Diphasiastrum) have long been used as greenery for Christmas decoration.
- The spores have long been used as a flash powder. See Lycopodium powder.
- The spores have been used by violin makers for centuries as a pore filler.
- In Cornwall, club mosses gathered during certain lunar phases were historically used as a remedy for eye disease.
Subfamily Lycopodielloideae Wagner & Beitel 1992 ex Øllgaard 2015
- Lateristachys Holub 1983
- Lycopodiella Holub 1964
- Palhinhaea Franco & Vasconcellos 1967 nom. cons.
- Pseudolycopodiella Holub 1983
Subfamily Lycopodioideae Eaton 1833 sensu Wagner & Beitel 1992 ex Øllgaard 2015
- Austrolycopodium Holub 1991
- Dendrolycopodium Haines 2003
- Diphasiastrum Holub 1975
- Diphasium Presl ex Rothmaler 1944
- Lycopodiastrum Holub 1975 ex Dixit 1981
- Lycopodium Linnaeus 1753 sensu stricto
- Pseudodiphasium Holub 1983
- Pseudolycopodium Holub 1983
- Spinulum Haines 2003
Subfamily Huperzioideae Rothmaler 1962 sensu Wagner & Beitel 1992 ex Øllgaard 2015
- James L. Reveal, Indices Nominum Supragenericorum Plantarum Vascularium
- PPG, I (2016). "A community-derived classification for extant lycophytes and ferns". Journal of Systematics and Evolution. 54: 563–603. doi:10.1111/jse.12229.
- Christenhusz, M. J. M. & Byng, J. W. (2016). "The number of known plants species in the world and its annual increase". Phytotaxa. Magnolia Press. 261 (3): 201–217. doi:10.11646/phytotaxa.261.3.1.
- Judd; et al. (2015). Plant Systematics: A Phylogenetic Approach. Sunderland, MA: Sinauer Associates is an imprint of Oxford University Press.
- "Lycopodiaceae". www.flora.dempstercountry.org. Retrieved 2017-12-20.
- Øllgaard, B. (1990). "Lycopodiaceae". In Pteridophytes and Gymnosperms: 31–39.
- Field; et al. (January 2016). "Molecular Phylogenetics and the Morphology of the Lycopodiaceae Subfamily Huperzioideae Supports Three Genera: Huperzia, Phlegmariurus and Phylloglossum". Molecular Phylogenetics and Evolution. 94, Part B: 635–57. doi:10.1016/j.ympev.2015.09.024.