• Plectonema Thuret ex Gomont, 1892
• Plectonema africanum Borge, 1928 accepted as Pseudophormidium africanum (Borge) Anagnostidis & Komárek, 1988
• Plectonema algeriense Behre, 1953
• Plectonema andinum Schwabe, 1960
• Plectonema araucanum Schwabe, 1960
• Plectonema batrachospermi Starmach, 1957 accepted as Pseudophormidium batrachospermi (Starmach) Anagnostidis & Komárek, 1988
• Plectonema battersii Gomont, 1899 accepted as Pseudophormidium battersii (Gomont) Anagnostidis, 2001
• Plectonema boryanum Gomont, 1899 accepted as Leptolyngbya boryana (Gomont) Anagnostidis & Komárek, 1988
• Plectonema boryanum f. hollerbachianum Elenkin, 1949 accepted as Pseudophormidium hollerbachianum (Elenkin) Anagnostidis, 2001
• Plectonema calotrichoides Gomont, 1899 accepted as Leptolyngbya calotrichoides (Gomont) Anagnostidis & Komárek, 1988
• Plectonema capitatum Jaag, 1935 accepted as Pseudoscytonema capitatum Anagnostidis & Komárek, 1988
• Plectonema capitatum Lemmermann, 1907
• Plectonema cloverianum Drouet, 1942
• Plectonema congregationis Schwabe, 1962 accepted as Pseudoscytonema congregationis (Schwabe) Anagnostidis & Komárek, 1988
• Plectonema corynoideum Beljakova, 1989
• Plectonema crispatum Playfair, 1915 accepted as Leptolyngbya crispata (Playfair) Anagnostidis & Komárek, 1988
• Plectonema dangeardii Frémy, 1930 accepted as Leptolyngbya dangeardii (Frémy) Anagnostidis & Komárek, 1988
• Plectonema desmidiacearum Noda, 1971 accepted as Leptolyngbya desmidiacearum (Noda) I.Umezaki & M.Watanabe, 1994
• Plectonema diplosiphon Woronichin, 1923 accepted as Schizothrix diplosiphon (Woronichin) Anagnostidis, 2001
• Plectonema edaphicum (Elenkin) Vaul. accepted as Pseudophormidium edaphicum (Elenkin) Anagnostidis & Komárek, 1988 accepted as Chroakolemma edaphicum (Elenkin) Becerra-Absalón & J.R.Johansen in Becerra-Absalón & al., 2018
• Plectonema endolithicum Ercegovic, 1932 accepted as Pseudoscytonema endolithicum (Ercegovic) Anagnostidis, 2005
• Plectonema flexuosum N.L.Gardner, 1927 accepted as Pseudophormidium flexuosum (N.L.Gardner) Anagnostidis & Komárek, 1988
• Plectonema fortii Frémy, 1930 accepted as Pseudophormidium fortii (Frémy) Anagnostidis & Komárek, 1988
• Plectonema gloeophilum Borzì, 1892 accepted as Leptolyngbya gloeophila (Borzì) Anagnostidis & Komárek, 1988
• Plectonema gloiophilum Borzì, 1892
• Plectonema golenkinianum Gomont, 1899 accepted as Pseudophormidium golenkinianum (Gomont) Anagnostidis, 2001
• Plectonema gracillimum Hansgirg, 1893 accepted as Leptolyngbya gracillima (Hansgirg) Anagnostidis & Komárek, 1988
• Plectonema hansgirgii Schmidle, 1900 accepted as Pseudophormidium hansgirgii (Schmidle) Anagnostidis & Komárek, 1988
• Plectonema indicum S.C.Dixit, 1936 accepted as Pseudophormidium indicum (S.C.Dixit) Anagnostidis & Komárek, 1988
• Plectonema kirchneri M.C.Cooke, 1882 (uncertain)
• Plectonema lanosum (Bory) Bornet & Thuret, 1880 accepted as
• Plectonema malayense Biswas, 1929 accepted as Pseudoscytonema malayense (Biswas) Elenkin, 1949
• Plectonema monodii Compére, 1970
• Plectonema murale N.L.Gardner, 1927 accepted as Leptolyngbya muralis (N.L.Gardner) Anagnostidis & Komárek, 1988
• Plectonema norvegicum Gomont, 1899 accepted as Leptolyngbya norvegica (Gomont) Anagnostidis & Komárek, 1988
• Plectonema nostocorum Bornet ex Gomont, 1892 accepted as Leptolyngbya nostocorum (Bornet ex Gomont) Anagnostidis & Komárek, 1988
• Plectonema nostocorum f. discolor Cedercreutz, 1929 accepted as Leptolyngbya nostocorum (Bornet ex Gomont) Anagnostidis & Komárek, 1988
• Plectonema notatum Schmidle, 1901 accepted as Leptolyngbya notata (Schmidle) Anagnostidis & Komárek, 1988
• Plectonema notatum var. africanum F.E.Fritsch & M.F.Rich, 1930 accepted as Leptolyngbya fritschii Anagnostidis, 2001
• Plectonema pauciramosum (Anissimova) Kondrateva, 1968 accepted as Pseudophormidium pauciramosum (Anissimova) Anagnostidis, 2001
• Plectonema phormidioides Hansgirg ex Gomont, 1892 accepted as Pseudophormidium phormidioides (Hansgirg ex Forti) Anagnostidis & Komárek, 1988
• Plectonema polymorphum Schwabe, 1960
• Plectonema polymorphum var. viride Schwabe, 1960 accepted as Pseudophormidium viride (Schwabe) M.T.P.Azevedo, 1991
• Plectonema purpureum Gomont, 1892 accepted as Pseudophormidium purpureum (Gomont) Anagnostidis & Komárek, 1988
• Plectonema purpureum f. pauciramosum Anissimova, 1949 accepted as Pseudophormidium pauciramosum (Anissimova) Anagnostidis, 2001
• Plectonema puteale (Kirchner) Hansgirg, 1885 (uncertain)
• Plectonema puteale f. edaphicum Elenkin, 1949 accepted as Pseudophormidium edaphicum (Elenkin) Anagnostidis & Komárek, 1988 accepted as Chroakolemma edaphicum (Elenkin) Becerra-Absalón & J.R.Johansen in Becerra-Absalón & al., 2018
• Plectonema radiosum Gomont, 1892 accepted as Pseudophormidium radiosum (Gomont) Anagnostidis & Komárek, 1988
• Plectonema rhenanum Schmidle, 1897 accepted as Pseudophormidium rhenanum (Schmidle) Anagnostidis, 2001
• Plectonema roseolum Gomont, 1892 accepted as Leptolyngbya carnea (Kützing ex Lemmermann) Anagnostidis & Komárek, 1988
• Plectonema rugosum C.-C.Jao, 1947
• Plectonema schmidlei Limanowska, 1912 accepted as Leptolyngbya schmidlei (Limanowska) Anagnostidis & Komárek, 1988
• Plectonema spelaeoides Cado, 1959 accepted as Pseudophormidium spelaeoides (Cado) Anagnostidis, 2001
• Plectonema spirale N.L.Gardner, 1927
• Plectonema spirale Schwabe & El Ayouty, 1966
• Plectonema spongiosum Schwabe, 1962 accepted as Pseudoscytonema spongiosum (Schwabe) Anagnostidis & Komárek, 1988
• Plectonema subtile Gayral & Mazancourt, 1958 (uncertain)
• Plectonema tatricum Starmach, 1963 accepted as Pseudophormidium tatricum (Starmach) Anagnostidis, 2001
• Plectonema tauricum Woronichin, 1932 accepted as Pseudophormidium tauricum (Woronichin) Anagnostidis & Komárek, 1988
• Plectonema tenue Thuret ex Gomont, 1892 accepted as Pseudophormidium tenue (Thuret ex Gomont) Anagnostidis & Komárek, 1988
• Plectonema tenuissimum N.L.Gardner, 1927 accepted as Leptolyngbya tenuissima (N.L.Gardner) Anagnostidis & Komárek, 1988
• Plectonema terebrans Bornet & Flahault ex Gomont, 1892 accepted as Leptolyngbya terebrans (Bornet & Flahault ex Gomont) Anagnostidis & Komárek, 1988
• Plectonema terebrans f. hansgirgiana Forti, 1907 (uncertain)
• Plectonema tomasinianum Bornet ex Gomont, 1893
• Plectonema tomasinianum var. annualavaginum Q.M.Li, 1983
• Plectonema tomasinianum var. gracile Hansgirg, 1891
• Plectonema tomasinianum var. vandalurense Desikachary, 1959
• Plectonema volkensii Schmidle, 1901
• Plectonema wollei Farlow ex Gomont, 1892 accepted as Microseira wollei (Farlow ex Gomont) G.B.McGregor & Sendall ex Kenins, 2017
• Plectonema wollei f. gracilis Frémy, 1930
• Plectonema wollei f. robustissima Frémy, 1930
• Plectonema wollei f. robustum G.S.West, 1907 accepted as Microseira wollei (Farlow ex Gomont) G.B.McGregor & Sendall ex Kenins, 2017
• Plectonema wollei var. minus D.S.Agarkar, 1967
• Plectonema yellowstonense Prát, 1929 accepted as Leptolyngbya yellowstonensis (Prát) Anagnostidis & Komárek, 1988