Lycopodium Cernuum

''Lycopodium'' (from Greek ''lykos'', wolf and ''podion'', diminutive of ''pous'', foot) is a genus of clubmosses, also known as ground pines or creeping cedars, in the family Lycopodiaceae. Two very different circumscriptions of the genus are in use. In the Pteridophyte Phylogeny Group classification of 2016 (PPG I), ''Lycopodium'' is one of nine genera in the subfamily Lycopodioideae, and has from nine to 15 species. In other classifications, the genus is equivalent to the whole of the subfamily, since it includes all of the other genera. More than 40 species are accepted.

Description

They are flowerless, vascular, terrestrial or epiphytic plants, with widely branched, erect, prostrate, or creeping stems, with small, simple, needle-like or scale-like leaves that cover the stem and branches thickly. The leaves contain a single, unbranched vascular strand, and are microphylls by definition. The kidney-shaped (reniform) spore-cases (sporangia) contain spores of one kind only, ( isosporous, homosporous), and are borne on the upper surface of the leaf blade of specialized leaves (sporophylls) arranged in a cone-like strobilus at the end of upright stems. The club-shaped appearance of these fertile stems gives the clubmosses their common name.

Lycopods reproduce asexually by spores. The plants have an underground sexual phase that produces gametes, and this alternates in the lifecycle with the spore-producing plant. The prothallium developed from the spore is a subterranean mass of tissue of considerable size, and bears both the male and female organs ( antheridia and archegonia). They are more commonly distributed vegetatively, though, through above- or below-ground rhizomes.

Taxonomy

The genus ''Lycopodium'' was first published by Carl Linnaeus in 1753. He placed it in the Musci (mosses) along with genera such as '' Sphagnum'', and included species such as ''Lycopodium selaginoides'', now placed in the genus ''Selaginella'' in a different order from ''Lycopodium''. Different sources use substantially different circumscriptions of the genus. Traditionally, ''Lycopodium'' was considered to be the only extant genus in the family Lycopodiaceae, so includes all the species in the family, although sometimes excluding one placed in the monotypic genus ''Phylloglossum''. Other sources divide Lycopodiaceae species into three broadly defined genera, ''Lycopodium'', ''Huperzia'' (including ''Phylloglossum'') and ''Lycopodiella''. In this approach, ''Lycopodium'' sensu lato has about 40 species. In the Pteridophyte Phylogeny Group classification of 2016 (PPG I), the broadly defined genus is equivalent to the subfamily Lycopodioideae, and ''Lycopodium'' is one of 16 genera in the family Lycopodiaceae, with between 9 and 15 species.

Species

Using the narrow circumscription of ''Lycopodium'', in which it is one of nine genera in the subfamily Lycopodioideae, the ''Checklist of Ferns and Lycophytes of the World'' recognized the following species :
*'' Lycopodium clavatum'' L. – stag's-horn clubmoss; subcosmopolitan
*''Lycopodium diaphanum'' (P.Beauv.) Sw. – Tristan da Cunha
*'' Lycopodium japonicum'' Thunb. – eastern Asia (Japan west and south to India and Sri Lanka)
*''Lycopodium lagopus'' (Laest. ex C.Hartm.) Zinserl. ex Kuzen. – circumpolar arctic and subarctic
*'' Lycopodium papuanum'' Nessel – New Guinea
*'' Lycopodium venustulum'' Gaudich. – Hawaii, Western Samoa, the Society Islands
*''Lycopodium vestitum'' Desv. ex Poir. – northwest South America (Andes)

Using the broader circumscription of the genus, ''Plants of the World Online'' recognized the following additional ''Lycopodium'' species . Using the narrow circumscription of the genus ''Lycopodium'', the ''Checklist of Ferns and Lycophytes of the World'' divided them among eight other genera:
*''Lycopodium alpinum'' L. = '' Diphasiastrum alpinum''
*''Lycopodium annotinum'' L. = ''Spinulum annotinum''
*''Lycopodium assurgens'' Fée = '' Austrolycopodium assurgens''
*''Lycopodium carolinum'' (Lawalrée) J.P.Roux = ''Diphasiastrum carolinum''
*''Lycopodium casuarinoides'' Spring = ''Lycopodiastrum casuarinoides''
*''Lycopodium complanatum'' L. = '' Diphasiastrum complanatum''
*''Lycopodium confertum'' Willd. = ''Austrolycopodium confertum''
*''Lycopodium dendroideum'' Michx. = '' Dendrolycopodium dendroideum''
*''Lycopodium deuterodensum'' Herter = ''Pseudolycopodium densum''
*''Lycopodium digitatum'' Dill. ex A.Braun = '' Diphasiastrum digitatum''
*''Lycopodium erectum'' Phil. = ''Austrolycopodium erectum''
*''Lycopodium fastigiatum'' R.Br. = ''Austrolycopodium fastigiatum''
*''Lycopodium fawcettii'' F.E.Lloyd & Underw. = '' Diphasiastrum fawcettii''
*''Lycopodium gayanum'' Brongn. = '' Diphasium gayanum''
*''Lycopodium habereri'' House = '' Diphasiastrum habereri''
*''Lycopodium hickeyi'' (Beitel & R.C.Moran) W.H.Wagner, Beitel & R.C.Moran = ''Dendrolycopodium hickeyi''
*''Lycopodium juniperoideum'' Sw. = ''Dendrolycopodium juniperoideum''
*''Lycopodium jussiaei'' Desv. = '' Diphasium jussiaei''
*''Lycopodium lawessonianum'' B.Øllg. = '' Diphasium lawessonianum''
*''Lycopodium madeirense'' J.H.Wilce = '' Diphasiastrum madeirense''
*''Lycopodium magellanicum'' (P.Beauv.) Sw. = '' Austrolycopodium magellanicum''
*''Lycopodium multispicatum'' J.H.Wilce = '' Diphasiastrum multispicatum''
*''Lycopodium nikoense'' Franch. & Sav. = '' Diphasiastrum nikoense''
*''Lycopodium obscurum'' L. = ''Dendrolycopodium obscurum''
*''Lycopodium oellgaardi'' (Stoor, Boudrie, Jérôme, K.Horn & Bennert) B.Bock = '' Diphasiastrum oellgaardii''
*''Lycopodium paniculatum'' Desv. = ''Austrolycopodium paniculatum''
*''Lycopodium platyrhizoma'' J.H.Wilce = '' Diphasiastrum platyrhizoma''
*''Lycopodium sabinifolium'' Willd. = '' Diphasiastrum sabinifolium''
*''Lycopodium scariosum'' G.Forst. = '' Diphasium scariosum''
*''Lycopodium sitchense'' Rupr. = '' Diphasiastrum sitchense''
*''Lycopodium spectabile'' Blume = '' Pseudodiphasium volubile''
*''Lycopodium subarcticum'' V.N.Vassil. = ''Spinulum annotinum'' ssp. ''alpestre''
*''Lycopodium thyoides'' Willd. = ''Diphasiastrum thyoides''
*''Lycopodium tristachyum'' Pursh = ''Diphasiastrum tristachyum''
*''Lycopodium volubile'' G.Forst. = '' Pseudodiphasium volubile''
*''Lycopodium yueshanense'' C.M.Kuo = ''Diphasiastrum yueshanense''
*''Lycopodium zanclophyllum'' J.H.Wilce = ''Diphasiastrum zanclophyllum''
*''Lycopodium'' × ''zeilleri'' (Rouy) Greuter & Burdet = '' Diphasiastrum zeilleri''

Uses

The spores of ''Lycopodium'' species are harvested and are sold as lycopodium powder.

''Lycopodium '' sp. herb has been used in the traditional Austrian medicine internally as tea or externally as compresses for treatment of disorders of the locomotor system, skin, liver and bile, kidneys and urinary tract, infections, rheumatism, and gout, though claims of efficacy are unproven. It has also been used in some United States government chemical warfare test programs such as Operation Dew. U.S. National Research Council, Subcommittee on Zinc Cadmium Sulfide
''Toxicologic Assessment of the Army's Zinc Cadmium Sulfide Dispersion''
National Academies Press, 1997, pp. 44–77, . ''Lycopodium'' powder was also used to determine the molecular size of oleic acid.

References

External links

Species list
(takes a broad view of the genus, including the species here separated in the genus '' Diphasiastrum'')

Burning ''Lycopodium'' Powder: Simulating a Grain Elevator Explosion
by Kevin A. Boudreaux

{{Taxonbar, from=Q624488

Lycopodiaceae
Lycophyte genera