• Ulothrix Kützing, 1833
• Ulothrix acrorhiza Kornmann, 1964 accepted as Ulothrix implexa (Kützing) Kützing, 1849
• Ulothrix acuminata K.R.Mattox & H.C.Bold, 1962 accepted as Uronema acuminatum (K.R.Mattox & H.C.Bold) G.M.Lokhorst, 1985
• Ulothrix aequalis Kützing, 1845
• Ulothrix aequalis var. cataeniformis (Kützing) Rabenhorst
• Ulothrix aequalis var. pallida Kützing (uncertain)
• Ulothrix albicans Kützing, 1845
• Ulothrix amphigranulata Skuja, 1948 accepted as Geminella amphigranulata (Skuja) Ramanathan, 1964
• Ulothrix anisartha Kützing (uncertain)
• Ulothrix aquatilis Tisdall
• Ulothrix attenuata Kützing
• Ulothrix australica Playfair, 1923
• Ulothrix australis Gain, 1911
• Ulothrix belkiae K.R.Mattox & Bold, 1962 accepted as Uronema belkiae (Mattox & Bold) O'Kelly & Floyd, 1984
• Ulothrix bicolor Ralfs (uncertain)
• Ulothrix bipyrenoidosa Fritsch & Rich, 1929
• Ulothrix brachymelia (Lyngbye) Trevisan (uncertain)
• Ulothrix braunii Kützing, 1849 accepted as Ulothrix moniliformis var. braunii (Kützing) Rabenhorst, 1868
• Ulothrix braunii var. parasitica Kützing accepted as Ulothrix moniliformis var. braunii (Kützing) Rabenhorst, 1868
• Ulothrix brunnthaleri Schussnig, 1915
• Ulothrix caldaria (Kützing) Collins
• Ulothrix capillaris Kützing, 1833 (uncertain)
• Ulothrix carmichaelii (Harvey) P.L.Crouan & H.M.Crouan (uncertain)
• Ulothrix cateniformis (Kützing) Kützing, 1849 accepted as Ulothrix aequalis Kützing, 1845
• Ulothrix chengiana Skvortsov
• Ulothrix collabens (C.Agardh) Thuret
• Ulothrix compacta (Roth) Kützing
• Ulothrix confervicola (Lagerheim) Mattox & Bold, 1962 accepted as Uronema confervicola Lagerheim, 1887
• Ulothrix consociata Wille, 1901 accepted as Ulothrix flacca (Dillwyn) Thuret, 1863
• Ulothrix consociata f. geniculata Jónsson, 1903 (uncertain)
• Ulothrix consociata f. minor H.Jónsson (uncertain)
• Ulothrix consociata var. islandica H.Jónsson (uncertain)
• Ulothrix consociata var. islandica Jónsson, 1903 accepted as Ulothrix flacca (Dillwyn) Thuret, 1863
• Ulothrix contorta (C.Agardh) Trevisan (uncertain)
• Ulothrix crassa (Kützing) Kützing
• Ulothrix crassa Kützing
• Ulothrix crassiuscula Kützing, 1852 (uncertain)
• Ulothrix crenulata (Kützing) Kützing, 1849 accepted as Hormidiopsis crenulata (Kützing) Heering, 1914
• Ulothrix crispa (Berkeley) Kützing, 1849 accepted as Ulothrix zonata (F.Weber & Mohr) Kützing, 1833
• Ulothrix cutleriae (Harvey) Thuret (uncertain)
• Ulothrix cylindrica Prescott, 1944
• Ulothrix cylindrica var. epiphyton A.K.Mahato & P.Mahato, 1991
• Ulothrix cylindrocapsa Itzigsohn (uncertain)
• Ulothrix debilis Kützing
• Ulothrix delicatula (Kützing) Kützing
• Ulothrix desmidiiformis Roemer
• Ulothrix didyma Kützing
• Ulothrix discifera Kjellman, 1877 accepted as Rosenvingiella discifera (Kjellman) Heesch, M.Pazoutová & Rindi, 2016
• Ulothrix discifera var. nivalis Wittrock, 1883 (uncertain)
• Ulothrix dissecta F.Gay, 1891
• Ulothrix dissiliens (J.E.Smith) Kützing, 1833 (uncertain)
• Ulothrix dotyi H.Silva, 1953 (uncertain)
• Ulothrix endospongialis Humm, 1979
• Ulothrix fimbriata Bold, 1958
• Ulothrix flacca (Dillwyn) Thuret, 1863
• Ulothrix flacca var. geniculata Berger-Perrot, 1980 (uncertain)
• Ulothrix flacca var. roscoffensis Berger-Perrot, 1980
• Ulothrix flaccida Kützing, 1849 accepted as Klebsormidium flaccidum (Kützing) P.C.Silva, K.R.Mattox & W.H.Blackwell, 1972
• Ulothrix flaccida var. fragilis (Kützing) Hansgirg, 1888 accepted as Klebsormidium fragile (Kützing) H.-P.Wagner & J.S.Zaneveld, 1988
• Ulothrix flaccida var. nitens (Kützing) Hansgirg, 1885 accepted as Ulothrix nitens Kützing, 1849 accepted as Klebsormidium nitens (Kützing) Lokhorst, 1996
• Ulothrix flexuosa Kornmann, 1964
• Ulothrix flexuosa Schussnig, 1915
• Ulothrix floccosa (Vaucher) Ørsted
• Ulothrix fragilis (J.D.Hooker & Harvey) Kützing
• Ulothrix fragilis Kützing, 1849 accepted as Klebsormidium fragile (Kützing) H.-P.Wagner & J.S.Zaneveld, 1988
• Ulothrix fusca Dickie, 1876 (uncertain)
• Ulothrix gelatinosa F.E.Fritsch
• Ulothrix geminata Jao, 1964
• Ulothrix geminata f. major H.J.Hu, 1984 accepted as Ulothrix geminata Jao, 1964
• Ulothrix geminata f. minor Y.-X.Wei, 1984 accepted as Ulothrix geminata Jao, 1964
• Ulothrix gigas (Vischer) K.R.Mattox & Bold, 1962
• Ulothrix glauca Nayal
• Ulothrix hieronymi (Lemmermann) Migula, 1907 (uncertain)
• Ulothrix idiospora G.S.West
• Ulothrix implexa (Kützing) Kützing, 1849
• Ulothrix inaequalis Kützing, 1845 accepted as Ulothrix zonata var. inaequalis (Kützing) Rabenhorst, 1868
• Ulothrix investiens (Fries) Trevisan
• Ulothrix irregularis Wille, 1880 accepted as Parallela transversalis (Brébisson) Novis, M.Lorenz, Broady & E.A. Flint, 2010
• Ulothrix islandica (H.Jónsson) Printz, 1926 accepted as Ulothrix flacca (Dillwyn) Thuret, 1863
• Ulothrix isogona (J.E.Smith) Thuret (uncertain)
• Ulothrix juergensii
• Ulothrix kochii Kützing, 1849 (uncertain)
• Ulothrix lacustris Hilse
• Ulothrix laeta Thuret, 1892 accepted as Urospora laeta (Thuret ex Bornet) Børgesen, 1925
• Ulothrix laetevirens (Harvey) Collins, 1909
• Ulothrix lamellosa Reinsch, 1890
• Ulothrix latissima Heufler, 1853 (uncertain)
• Ulothrix lenormandii (Kützing) Kützing
• Ulothrix ligustica Dufour
• Ulothrix limnetica Lemmermann, 1914
• Ulothrix limnetica var. minor Teiling
• Ulothrix longicauda Schussnig, 1915
• Ulothrix marina P.Crouan & H.Crouan accepted as Gloeotila marina P.Crouan & H.Crouan, 1867
• Ulothrix maxima Kützing (uncertain)
• Ulothrix minuta K.R.Mattox & Bold, 1962 accepted as
• Ulothrix minutula Kützing, 1845
• Ulothrix mirabilis Hansgirg, 1886
• Ulothrix moniliformis (Kützing) Kützing, 1849
• Ulothrix moniliformis f. subramosa Suringar (uncertain)
• Ulothrix moniliformis var. braunii (Kützing) Rabenhorst, 1868