1. Forma Scenedesmus quadricauda f. crassiaculeatus Uherkovich, 1956
2. Forma Scenedesmus quadricauda f. minus Ralfs
3. Forma Scenedesmus quadricauda f. vidyanagarensis Isabella & R.J.Patel, 1988
4. Variety Scenedesmus quadricauda var. claviculiferus Nitardy, 1940
5. Variety Scenedesmus quadricauda var. dispar Brébisson
6. Variety Scenedesmus quadricauda var. ecornis Francé
7. Variety Scenedesmus quadricauda var. horridus Kirchner
8. Variety Scenedesmus quadricauda var. incurvus Playfair
9. Variety Scenedesmus quadricauda var. inermius Playfair
10. Variety Scenedesmus quadricauda var. longispinus G.M.Smith
11. Variety Scenedesmus quadricauda var. microspina B.Martens & Pankow, 1972
12. Forma Scenedesmus quadricauda f. major Isabella & R.J.Patel, 1988 accepted as Desmodesmus perforatus (Lemmermann) E.Hegewald, 2000
13. Forma Scenedesmus quadricauda f. major W.B.Turner, 1893 accepted as Desmodesmus perforatus (Lemmermann) E.Hegewald, 2000 (synonym)
14. Variety Scenedesmus quadricauda var. abundans (Kirchner) Hansgirg, 1888 accepted as Desmodesmus abundans (Kirchner) E.H.Hegewald, 2000 (synonym)
15. Variety Scenedesmus quadricauda var. acutispinus Roll, 1925 accepted as Desmodesmus intermedius var. acutispinus (Roll) E.Hegewald, 2000 (synonym)
16. Variety Scenedesmus quadricauda var. armatus (Chodat) Dedusenko, 1953 accepted as Scenedesmus armatus (Chodat) Chodat, 1913 accepted as Desmodesmus armatus (Chodat) E.H.Hegewald, 2000
17. Variety Scenedesmus quadricauda var. asymmetricus Schröder, 1897 accepted as Desmodesmus asymmetricus (Schröder) E.Hegewald, 2000 (synonym)
18. Variety Scenedesmus quadricauda var. bicaudata Hansgirg, 1890 accepted as Scenedesmus bicaudatus Dedusenko, 1925 accepted as Desmodesmus bicaudatus (Dedusenko) P.M.Tsarenko, 2000 (synonym)
19. Variety Scenedesmus quadricauda var. coutei Tell, 1979 accepted as Desmodesmus perforatus var. iberaënsis (Tell) E.Hegewald & S.L.Jeon, 2006 (synonym)
20. Variety Scenedesmus quadricauda var. delicatissimus Massjuk, 1962 accepted as Desmodesmus opoliensis var. delicatissimus (Massjuk) Täuscher, 2009 (synonym)
21. Variety Scenedesmus quadricauda var. dentatus Dedusenko accepted as Scenedesmus caudato-aculeolatus Chodat, 1926 (synonym)
22. Variety Scenedesmus quadricauda var. inermis Playfair, 1913 accepted as Scenedesmus bijugus var. inermis (Playfair) V.May, 1973 (homotypic or heterotypic synonym)
23. Variety Scenedesmus quadricauda var. inflatus Svirenko, 1924 accepted as Desmodesmus intermedius var. inflatus (Svirenko) E.Hegewald, 2000
24. Variety Scenedesmus quadricauda var. insignis West & G.S.West, 1895 accepted as Desmodesmus insignis (West & G.S.West) E.Hegewald, 2000 (synonym)
25. Variety Scenedesmus quadricauda var. longispina (Chodat) G.M.Smith, 1916 accepted as Desmodesmus armatus var. longispina (Chodat) E.Hegewald, 2000
26. Variety Scenedesmus quadricauda var. maximus (West & G.S.West) Chodat accepted as Scenedesmus magnus Meyen, 1829 accepted as Desmodesmus magnus (Meyen) Tsarenko, 2000 (synonym)
27. Variety Scenedesmus quadricauda var. maximus West & G.S.West, 1895 accepted as Desmodesmus maximus (West & G.S.West) Hegewald, 2000 (synonym)
28. Variety Scenedesmus quadricauda var. microspina (Chodat) Philipose, 1967 accepted as Desmodesmus microspina (Chodat) Tsarenko, 2000 (synonym)
29. Variety Scenedesmus quadricauda var. naegelii (Brébisson) Rabenhorst, 1868 accepted as Scenedesmus naegelii Brébisson, 1856 (synonym)
30. Variety Scenedesmus quadricauda var. nagelii (Brébisson) Rabenhorst, 1868 accepted as Scenedesmus naegelii Brébisson, 1856 (synonym)
31. Variety Scenedesmus quadricauda var. oahuensis Lemmermann accepted as Scenedesmus magnus Meyen, 1829 accepted as Desmodesmus magnus (Meyen) Tsarenko, 2000 (synonym)
32. Variety Scenedesmus quadricauda var. opoliensis (P.G.Richter) West & G.S.West, 1902 accepted as Desmodesmus opoliensis (P.G.Richter) E.Hegewald, 2000
33. Variety Scenedesmus quadricauda var. parvus G.M.Smith, 1916 accepted as Scenedesmus parvus (G.M.Smith) Bourrelly, 1952
34. Variety Scenedesmus quadricauda var. quadrispina (Chodat) G.M.Smith, 1916 accepted as Scenedesmus quadrispina Chodat, 1913 accepted as Desmodesmus abundans (Kirchner) E.H.Hegewald, 2000 (synonym)
35. Variety Scenedesmus quadricauda var. rectangularis G.S.West, 1914 accepted as Desmodesmus communis var. rectangularis (G.S.West) E.Hegewald, 2000
36. Variety Scenedesmus quadricauda var. setosus (Kirchner) Hansgirg, 1888 accepted as Scenedesmus magnus Meyen, 1829 accepted as Desmodesmus magnus (Meyen) Tsarenko, 2000 (synonym)
37. Variety Scenedesmus quadricauda var. vesiculosus Proshkina-Lavrenko accepted as Scenedesmus vesiculosus (Proshkina-Lavrenko) Péterfi, 1964 (synonym)
38. Variety Scenedesmus quadricauda var. westii G.M.Smith, 1916 accepted as Scenedesmus maximus (West & G.S.West) Chodat, 1913 accepted as Desmodesmus maximus (West & G.S.West) Hegewald, 2000 (synonym)
39. Forma Scenedesmus quadricauda f. bicaudatus Isabella & R.J.Patel, 1989 (uncertain)
40. Forma Scenedesmus quadricauda f. granulatus Hortobágyi, 1967 (uncertain)
41. Variety Scenedesmus quadricauda var. acutiformis (Schröder) Schmidle (uncertain, uncertain taxonomic status subjected to verification)
42. Variety Scenedesmus quadricauda var. ellipticus West & G.S.West, 1895 (uncertain)
43. Variety Scenedesmus quadricauda var. variabilis Hansgirg, 1892 (uncertain, uncertain taxonomic status subjected to verification)

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