Diphasiastrum is a genus of clubmosses in the plant family Lycopodiaceae. In the Pteridophyte Phylogeny Group classification of 2016 (PPG I), it is placed in the subfamily Lycopodioideae. It is closely related to the genus Lycopodium, and some botanists treat it within a broad view of that genus as a section, Lycopodium sect. Complanata. Some species superficially resemble diminutive gymnosperms and have been given common names such as ground-pine or ground-cedar. There are 16 species, and numerous natural hybrids in the genus; many of the hybrids are fertile, allowing their occurrence to become frequent, sometimes more so than the parent species. The basal chromosome count for this genus is n=23, which is distinctively different from other lycopods. Several species have been used economically for their spores, which are harvested as Lycopodium powder. Species , the Checklist of Ferns and Lycophytes of the World recognized the following species: Diphasiastrum alpinum (L.) Holub – alpine clubmoss; circumpolar, subarctic and alpine Diphasiastrum angustiramosum (Alderw.) Holub – New Guinea Diphasiastrum carolinum (Lawalrée) Holub Diphasiastrum complanatum (L.) Holub – flat-stemmed clubmoss, northern running-pine, or ground cedar; circumpolar, cool temperate Diphasiastrum digitatum (Dill. ex A.Br.) Holub – fan clubmoss, southern running-pine, or running cedar; eastern Canada, northeastern United States, Appalachian Mountains Diphasiastrum falcatum B.Øllg. & P.G.Windisch Diphasiastrum fawcettii (F.E.Lloyd & Underw.) Holub – Jamaica, Hispaniola Diphasiastrum henryanum (E.D.Br. & F.Br.) Holub – Marquesas Islands Diphasiastrum madeirense (J.H.Wilce) Holub – Madeira, Azores Diphasiastrum multispicatum (J.H.Wilce) Holub – Taiwan, Philippines Diphasiastrum nikoense (Franch. & Sav.) Holub – Japan Diphasiastrum platyrhizoma (J.H.Wilce) Holub – Borneo, Sumatra Diphasiastrum sitchense (Rupr.) Holub – Alaskan clubmoss; northern North America Diphasiastrum thyoides (Humb. & Bonpl. ex Willd.) Holub – Caribbean, Central and South America Diphasiastrum tristachyum (Pursh) Holub – blue clubmoss, blue ground-cedar; circumpolar, cool temperate Diphasiastrum veitchii (Christ) Holub – Veitch's clubmoss; eastern Himalayas east to Taiwan Diphasiastrum wightianum (Wall. ex Hook. & Grev.) Holub – southeast Asia, New Guinea Diphasiastrum yueshanense (C.M.Kuo) Holub – Taiwan Diphasiastrum zanclophyllum (J.H.Wilce) Holub Selected hybrids Some species are treated as hybrids, although not by all sources: Diphasiastrum × habereri (House) Holub (D. digitatum × D. tristachyum) Diphasiastrum × issleri (Rouy) Holub (syn. D. issleri, D. alpinum × D. complanatum) Diphasiastrum × oellgaardii Stoor, Boudrie, Jérôme, K.Horn & Bennert (D. alpinum × D. tristachyum) Diphasiastrum × sabinifolium (Willd.) Holub (syn. D. sabinifolium, D. sitchense × D. tristachyum) Diphasiastrum × takedae Ivanenko (D. alpinum × D. sitchense)