• Halymenia C.Agardh, 1817
• Halymenia abyssicola E.Y.Dawson, 1944
• Halymenia actinophysa M.A.Howe, 1911
• Halymenia acuminata (Holmes) J.Agardh, 1901 accepted as Grateloupia acuminata Holmes, 1896
• Halymenia agardhii De Toni, 1905 accepted as Sebdenia flabellata (J.Agardh) P.G.Parkinson, 1980
• Halymenia algeriensis Montagne, 1838 accepted as Chrysymenia pinnulata (C.Agardh) J.Agardh, 1842 accepted as Chrysymenia ventricosa (J.V.Lamouroux) J.Agardh, 1842
• Halymenia amoena Bory de Saint-Vincent, 1834 accepted as Sebdenia amoena (Bory) E.Soler-Onís, 1998
• Halymenia angusta (J.Agardh) De Toni, 1905
• Halymenia arachnophylloidea Weber-van Bosse, 1921
• Halymenia asymmetrica Gargiulo, Masi & Tripodi, 1986
• Halymenia australis (Sonder) Sonder, 1848 accepted as Nizymenia conferta (Sonder) Chiovitti, G.W.Saunders & Kraft, 1995
• Halymenia ballesterosii Rodríguez-Prieto, Showe M.Lin, De Clerck & Huisman, 2020
• Halymenia bermudensis Collins & M.Howe, 1916 accepted as Cryptonemia bermudensis (Collins & M.Howe) C.W.Schneider, C.E.Lane & G.W.Saunders, 2018
• Halymenia bifida E.Y.Dawson, 1954
• Halymenia botryoides Richard, 1834
• Halymenia brasiliana S.M.P.B.Guimarães & M.T.Fujii, 1998
• Halymenia brodiei (Turner) Lamouroux, 1824 accepted as Coccotylus brodiei (Turner) Kützing, 1843
• Halymenia bullosa (Harvey) Huisman, Rodríguez-Prieto & Showe M.Lin, 2022
• Halymenia californica G.M.Smith & Hollenberg, 1943
• Halymenia calvadosii (J.V.Lamouroux ex Duby) Montagne, 1836 accepted as Helminthocladia calvadosii (J.V.Lamouroux ex Duby) Setchell, 1915
• Halymenia carnosa
• Halymenia carnosa var. dentata (Suhr) Kützing, 1849 accepted as Sarcodia dentata (Suhr) R.E.Norris ex M.J.Wynne, 1989
• Halymenia cavernicola Giaccone, 1968 accepted as Halymenia elongata C.Agardh, 1822
• Halymenia cearensis C.A.A.Azevedo, Cassano & M.C.Oliveira, 2016
• Halymenia cerratei C.O.Acleto, 1973
• Halymenia cervicornis J.Agardh, 1842 accepted as Platoma cyclocolpum (Montagne) F.Schmitz, 1894
• Halymenia ceylanica Harvey ex Kützing, 1866 accepted as Halymenia microcarpa (Montagne) P.C.Silva, 1987
• Halymenia chiangiana I.A.Abbott & Kraft, 1997
• Halymenia chondricola Sonder, 1845 accepted as Hymenocladia chondricola (Sonder) J.A.Lewis, 1994
• Halymenia chondricola var. elongata Sonder, 1845
• Halymenia chondriopsidea J.Agardh, 1892 accepted as Zymurgia chondriopsidea (J.Agardh) J.A.Lewis & Kraft, 1992
• Halymenia clathrata E.C.Oliveira, Pinheiro-Vieira & R.E.Norris, 1976
• Halymenia claviformis Suhr, 1831
• Halymenia cliftonii Harvey, 1859 accepted as Cryptonemia kallymenioides (Harvey) Kraft, 1982
• Halymenia coccinea (Harvey) I.A.Abbott, 1967 accepted as Weeksia coccinea (Harvey) S.C.Lindstrom, 1986
• Halymenia cordata (Turner) C.Agardh, 1822 accepted as Iridaea cordata (Turner) Bory, 1826
• Halymenia corinaldii Meneghini, 1844
• Halymenia cromwellii I.A.Abbott, 1998
• Halymenia cyclocolpa Montagne, 1841 accepted as Platoma cyclocolpum (Montagne) F.Schmitz, 1894
• Halymenia decipiens J.Agardh, 1851 accepted as Halymenia elongata var. decipiens (J.Agardh) Cremades, 1990
• Halymenia dentata Suhr, 1834 accepted as Sarcodia dentata (Suhr) R.E.Norris ex M.J.Wynne, 1989
• Halymenia dichotoma (J.Agardh) J.Agardh, 1876 accepted as Sebdenia dichotoma Berthold, 1884
• Halymenia dichotoma (J.Agardh) Montagne, 1846 accepted as Nemastoma dichotomum J.Agardh, 1842
• Halymenia dichotoma var. maior Ercegovic, 1963 accepted as Sebdenia dichotoma var. maior (Ercegovic) Antolic & Span, 2013
• Halymenia digitata J.Agardh, 1892 accepted as Cryptonemia digitata (J.Agardh) Womersley & J.A.Lewis, 1994
• Halymenia dilatata Zanardini, 1851
• Halymenia doryphora Montagne, 1839 accepted as Grateloupia doryphora (Montagne) M.Howe, 1914
• Halymenia dubia Bory de Saint-Vincent, 1834
• Halymenia dubyi Chauvin ex Duby, 1830 accepted as Schizymenia dubyi (Chauvin ex Duby) J.Agardh, 1851
• Halymenia duchassaingii (J.Agardh) Kylin, 1932
• Halymenia durvillaei accepted as Halymenia durvillei Bory de Saint-Vincent, 1828
• Halymenia durvillei Bory de Saint-Vincent, 1828
• Halymenia durvillei var. ceylanica (Harvey ex Kützing) Weber-van Bosse, 1921 accepted as Halymenia microcarpa (Montagne) P.C.Silva, 1987
• Halymenia durvillei var. fimbriata Zanardini (uncertain)
• Halymenia durvillei var. formosa (Harvey ex Kützing) Reinbold, 1896 accepted as Halymenia formosa Harvey ex Kützing, 1866
• Halymenia echinophysa Collins & M.Howe, 1916
• Halymenia edulis (Stackhouse) C.Agardh, 1822 accepted as Dilsea carnosa (Schmidel) Kuntze, 1898
• Halymenia edulis var. media C.Agardh, 1822 accepted as Nemastoma minus J.Agardh, 1842 accepted as Schizymenia dubyi (Chauvin ex Duby) J.Agardh, 1851
• Halymenia elongata C.Agardh, 1822
• Halymenia elongata Kützing, 1849 accepted as Halymenia lapathifolia Kützing, 1866 accepted as Mariaramirezia lapathifolia (Kützing) Molinari & Guiry, 2021
• Halymenia elongata var. decipiens (J.Agardh) Cremades, 1990
• Halymenia elongata var. plana Cremades, 1990 (uncertain)
• Halymenia fasciata Bory de Saint-Vincent
• Halymenia fastigiata Bory de Saint-Vincent, 1825 accepted as Nothogenia fastigiata (Bory) P.G.Parkinson, 1983
• Halymenia fastigiata J.Agardh, 1849 accepted as Halymenia elongata C.Agardh, 1822
• Halymenia filiformis (Hornemann) C.Agardh, 1822 accepted as Dumontia contorta (S.G.Gmelin) Ruprecht, 1850
• Halymenia filiformis var. incrassata (O.F.Müller) C.Agardh, 1822 accepted as Dumontia contorta (S.G.Gmelin) Ruprecht, 1850
• Halymenia filiformis var. tenuis C.Agardh, 1822
• Halymenia fimbriata (Zanardini) Aleem, 1993 accepted as Halymenia durvillei var. fimbriata Zanardini
• Halymenia fimbriata Zanardini, 1874 accepted as Sarcodia ciliata Zanardini, 1874
• Halymenia flabellata F.Schmitz, 1895
• Halymenia floresia (Clemente) C. Agardh, 1807 accepted as Halymenia floresii (Clemente) C.Agardh, 1817
• Halymenia floresii (Clemente) C.Agardh, 1817
• Halymenia floresii subsp. harveyana (J.Agardh) Womersley & Lewis, 1994 accepted as Halymenia harveyana J.Agardh, 1892
• Halymenia floresii var. angusta C.Agardh, 1822 accepted as Calosiphonia vermicularis (J.Agardh) F.Schmitz, 1889
• Halymenia floresii var. pinnata Codomier, 1974 (uncertain)
• Halymenia floresii var. ulvoidea Codomier, 1974
• Halymenia floridana J.Agardh, 1892
• Halymenia foeniculacea (Hudson) C.Agardh, 1817 accepted as Dictyosiphon foeniculaceus (Hudson) Greville, 1830
• Halymenia foliacea W.R.Taylor, 1947
• Halymenia formosa Harvey ex Kützing, 1866
• Halymenia furcellata (Turner) C.Agardh, 1821 accepted as Scinaia furcellata (Turner) J.Agardh, 1851
• Halymenia furcellata var. capensis C.Agardh, 1822 accepted as Ahnfeltiopsis complicata (Kützing) P.C.Silva & DeCew, 1992
• Halymenia furcellata var. cartilaginea C.Agardh, 1822 accepted as Scinaia furcellata (Turner) J.Agardh, 1851
• Halymenia furcellata var. subcostata J.Agardh, 1842 accepted as Scinaia interrupta (A.P.de Candolle) M.J.Wynne, 1989
• Halymenia gardneri (Kylin) P.G.Parkinson, 1980
• Halymenia gelinaria F.S.Collins & M.A.Howe, 1916 accepted as Halymenia floridana J.Agardh, 1892
• Halymenia gmelinii Duby, 1830 accepted as Cryptonemia palmetta (S.G.Gmelin) Woelkering, G.Furnari, Cormaci & McNeill, 2019
• Halymenia graminifolia (Lepechin) Steudel, 1824 accepted as Devaleraea ramentacea (Linnaeus) Guiry, 1982
• Halymenia hakalauensis Tilden, 1894 accepted as Polyopes hakalauensis (Tilden) I.A.Abbott, 1998
• Halymenia hancockii W.R.Taylor, 1942
• Halymenia harveyana J.Agardh, 1892
• Halymenia hawaiiana Hernández-Kantun & A.R.Sherwood, 2012
• Halymenia heterocarpa Chuvin ex Duby, 1830 accepted as Drachiella heterocarpa (Chauvin ex Duby) Maggs & Hommersand, 1993
• Halymenia hollenbergii I.A.Abbott, 1967
• Halymenia hvarii Ercegovic, 1963
• Halymenia ignifera C.A.A.Azevedo, Cassano & M.C.Oliveira, 2016
• Halymenia imbricata Dickie, 1887
• Halymenia incrustans J.Agardh, 1885 accepted as Titanophora incrustans (J.Agardh) Børgesen, 1949
• Halymenia incurvata Suhr, 1839 accepted as Durvillaea antarctica (Chamisso) Hariot, 1892