1. Species Callithamnion acutum Kylin, 1925
2. Species Callithamnion africanum Stegenga, Reddy, R.J.Anderson & Bolton, 2020
3. Species Callithamnion aglaothamnioides Itono, 1971
4. Species Callithamnion apiculatum P.L.Crouan & H.M.Crouan, 1878
5. Species Callithamnion arborescens N.L.Gardner, 1927
6. Species Callithamnion arrawarricum A.J.K.Millar, 1990
7. Species Callithamnion biseriatum Kylin, 1925
8. Species Callithamnion bisporum N.L.Gardner, 1927
9. Species Callithamnion brachygonum Harvey, 1855
10. Species Callithamnion callithamnioides (A.B.Joly & Ugadim) M.J.Wynne, 2005
11. Species Callithamnion catalinense E.Y.Dawson, 1962
12. Species Callithamnion caulescens (J.Agardh) Womersley, 1998
13. Species Callithamnion codicola Grunow, 1874
14. Species Callithamnion colensoi Harvey, 1855
15. Species Callithamnion collabens (Rudolphi) L.M.McIvor & Maggs, 2002
16. Species Callithamnion compactum E.Y.Dawson, 1962
17. Species Callithamnion consanguineum Harvey, 1855
18. Species Callithamnion corymbosum (Smith) Lyngbye, 1819
19. Species Callithamnion crispulum Harvey, 1855
20. Species Callithamnion cryptopterum Kützing, 1849
21. Species Callithamnion dasytrichum Montagne
22. Species Callithamnion debile Harvey, 1855
23. Species Callithamnion ecuadoreanum W.R.Taylor, 1945
24. Species Callithamnion ellipticum Montagne, 1841
25. Species Callithamnion elongellum Zanardini, 1846
26. Species Callithamnion epiphyticum W.R.Taylor, 1945
27. Species Callithamnion exiguum Stegenga, Bolton & R.J.Anderson, 1997
28. Species Callithamnion flabellatum A.C.Brown & N.Jarman
29. Species Callithamnion flagellare Zanardini, 1846
30. Species Callithamnion gaudichaudii C.Agardh, 1828
31. Species Callithamnion gracile Hooker f. & Harvey, 1845
32. Species Callithamnion granulatum (Ducluzeau) C.Agardh, 1828
33. Species Callithamnion griffithsioides (J.Agardh) H.B.S.Womersley, 1998
34. Species Callithamnion hamelii Nasr, 1941
35. Species Callithamnion hypneae P.L.Crouan & H.M.Crouan, 1865
36. Species Callithamnion implicatum (Kützing) J.Agardh, 1851
37. Species Callithamnion japonicum Noda, 1971
38. Species Callithamnion kirillianum A.D.Zinova & Zaberzhinskaya, 1968
39. Species Callithamnion korffense A.J.K.Millar, 1990
40. Species Callithamnion larcinum Harvey, 1855
41. Species Callithamnion lasioides Reinsch, 1875
42. Species Callithamnion marshallense E.Y.Dawson, 1957
43. Species Callithamnion mildbraedii Pilger, 1920
44. Species Callithamnion montagnei Hooker f., 1847
45. Species Callithamnion mytili Schousboe
46. Species Callithamnion myuroides Zanardini ex Frauenfeld, 1855
47. Species Callithamnion nipponicum Noda, 1971
48. Species Callithamnion pacificum W.R.Taylor, 1945
49. Species Callithamnion paschale Børgesen, 1924
50. Species Callithamnion pennula Grunow, 1868
51. Species Callithamnion perpusillum P.C.Silva, 1996
52. Species Callithamnion pikeanum Harvey, 1853
53. Species Callithamnion pinastroides
54. Species Callithamnion pinnatum Womersley, 1998
55. Species Callithamnion planum Montagne, 1837
56. Species Callithamnion plumulum
57. Species Callithamnion puniceum Harvey, 1855
58. Species Callithamnion purpuriferum Harvey, 1838
59. Species Callithamnion pylaisaeanum Montagne
60. Species Callithamnion ramosissimum N.L.Gardner, 1927
61. Species Callithamnion reductum Baardseth, 1941
62. Species Callithamnion rigescens Zanardini
63. Species Callithamnion roseum Harvey, 1849
64. Species Callithamnion rupicola C.L.Anderson, 1894
65. Species Callithamnion rupinicola C.L.Anderson, 1894
66. Species Callithamnion semicorticatum Baardseth, 1941
67. Species Callithamnion soccoriense W.R.Taylor, 1945
68. Species Callithamnion spinuliferum Ardissone, 1888
69. Species Callithamnion stuposum Suhr, 1840
70. Species Callithamnion subsecundum Grunow, 1889
71. Species Callithamnion tetragonum (Stackhouse) S.F.Gray, 1821
72. Species Callithamnion tetricum (Dillwyn) S.F.Gray, 1821
73. Species Callithamnion unilaterale Zanardini, 1846
74. Species Callithamnion variegatum Suhr, 1840
75. Species Callithamnion veleroae E.Y.Dawson, 1944
76. Species Callithamnion vieillardii Kützing, 1863
77. Species Callithamnion abbreviatum Kützing, 1843 accepted as Antithamnion cruciatum (C.Agardh) Nägeli, 1847 (synonym)
78. Species Callithamnion abietinum Reinsch, 1875 accepted as Pterothamnion crispum (Ducluzeau) Nägeli, 1862
79. Species Callithamnion acanthophorum Kützing, 1849 accepted as Macrothamnion acanthophorum (Kützing)Womersley, 1998
80. Species Callithamnion acrospermum J.Agardh, 1851 accepted as Callithamnion hookeri (Dillwyn) S.F.Gray, 1821 accepted as Aglaothamnion hookeri (Dillwyn) Maggs & Hommersand, 1993 accepted as Gaillona hookeri (Dillwyn) Athanasiadis, 2016 (synonym)
81. Species Callithamnion aculeatum Harvey, 1855 accepted as Trithamnion aculeatum (Harvey) Womersley & Wollaston, 1998
82. Species Callithamnion adnatum J.Agardh, 1879 accepted as Antithamnionella ternifolia (Hooker f. & Harvey) Lyle, 1922
83. Species Callithamnion aegagrophilae Funk, 1922 accepted as Callithamniella tingitana (Schousboe ex Bornet) Feldmann-Mazoyer, 1938
84. Species Callithamnion aegagropila J.Agardh, 1876 accepted as Lejolisia aegagropila (J.Agardh) J.Agardh, 1892
85. Species Callithamnion affine Harvey, 1833 accepted as Callithamnion tetragonum (Stackhouse) S.F.Gray, 1821
86. Species Callithamnion affine Kützing, 1843 accepted as Colaconema savianum (Meneghini) R.Nielsen, 1994 (synonym)
87. Species Callithamnion americanum Harvey, 1853 accepted as Scagelia americana (Harvey) Athanasiadis, 1996
88. Species Callithamnion angustatum Hooker f. & Harvey, 1847 accepted as Hirsutithallia angustata (J.D.Hooker & Harvey) Wollaston & Womersley, 1998
89. Species Callithamnion apicale Noda, 1973 accepted as Aglaothamnion callophyllidicola (Yamada) Boo, I.K.Lee, Rueness & Yoshida, 1991 (synonym)
90. Species Callithamnion apiculatum Meneghini, 1844 accepted as Seirospora apiculata (Meneghini) Feldmann-Mazoyer, 1941
91. Species Callithamnion applicitum Harvey, 1855 accepted as Antithamnion pectinatum (Montagne) Brauner, 1994
92. Species Callithamnion arachnoideum C.Agardh, 1828 accepted as Aglaothamnion tenuissimum (Bonnemaison) Feldmann-Mazoyer, 1941
93. Species Callithamnion arbuscula (Dillwyn) Lyngbye, 1819 accepted as Aglaothamnion sepositum (Gunnerus) Maggs & Hommersand, 1993 accepted as Gaillona seposita (Gunnerus) Athanasiadis, 2016
94. Species Callithamnion armatum J.Agardh, 1885 accepted as Antithamnion armatum (J.Agardh) De Toni, 1903
95. Species Callithamnion arnottii Trevisan, 1845 accepted as Aglaothamnion tenuissimum (Bonnemaison) Feldmann-Mazoyer, 1941
96. Species Callithamnion australe J.Agardh, 1841 accepted as Shepleya australis (J.Agardh) E.M.Gordon, 1972
97. Species Callithamnion baccatum J.Agardh, 1870 accepted as Vickersia baccata (J.Agardh) Karsakoff, 1896
98. Species Callithamnion baileyi Harvey, 1853 accepted as Callithamnion tetragonum (Stackhouse) S.F.Gray, 1821
99. Species Callithamnion ballioides Sonder, 1853 accepted as Inkyuleea ballioides (Sonder) H.-G.Choi, Kraft & G.W.Saunders, 2000
100. Species Callithamnion barbatum C.Agardh, 1828 accepted as Ptilothamnion pluma (Dillwyn) Thuret, 1863
101. Species Callithamnion beauii P.L.Crouan & H.M.Crouan, 1865 accepted as Wrangelia argus (Montagne) Montagne, 1856
102. Species Callithamnion bebbii Reinsch, 1875 accepted as Pterothamnion crispum (Ducluzeau) Nägeli, 1862
103. Species Callithamnion bipinnatum P.L.Crouan & H.M.Crouan, 1867 accepted as Aglaothamnion bipinnatum (P.Crouan & H.Crouan) Feldmann & G.Feldmann, 1948 (synonym)
104. Species Callithamnion boergesenii Aponte & Ballantine, 1990 accepted as Aglaothamnion boergesenii (Aponte & D.L.Ballantine) L'Hardy-Halos & Rueness, 1997
105. Species Callithamnion borreri (Smith) C.Agardh, 1828 accepted as Pleonosporium borreri (Smith) Nägeli, 1862 (synonym)
106. Species Callithamnion botryocarpum Harvey, 1855 accepted as Colaconema caespitosum (J.Agardh) Jackelman, Stegenga & J.J.Bolton, 1991
107. Species Callithamnion brachiatum (Bonnemaison) Harvey, 1847 accepted as Callithamnion tetragonum (Stackhouse) S.F.Gray, 1821
108. Species Callithamnion breviramosum N.L.Gardner, 1927 accepted as Callithamnion rupinicola C.L.Anderson, 1894
109. Species Callithamnion brodiei Harvey, 1833 accepted as Aglaothamnion hookeri (Dillwyn) Maggs & Hommersand, 1993 accepted as Gaillona hookeri (Dillwyn) Athanasiadis, 2016 (synonym)
110. Species Callithamnion brownianum Harvey, 1855 accepted as Spongoclonium brownianum (Harvey) J.Agardh, 1892
111. Species Callithamnion byssoides Arnott ex Harvey, 1833 accepted as Aglaothamnion tenuissimum (Bonnemaison) Feldmann-Mazoyer, 1941 (synonym)
112. Species Callithamnion caespitosum J.Agardh, 1851 accepted as Colaconema caespitosum (J.Agardh) Jackelman, Stegenga & J.J.Bolton, 1991
113. Species Callithamnion californicum N.L.Gardner, 1927 accepted as Callithamnion acutum Kylin, 1925
114. Species Callithamnion callophyllidicola Yamada, 1932 accepted as Aglaothamnion callophyllidicola (Yamada) Boo, I.K.Lee, Rueness & Yoshida, 1991
115. Species Callithamnion caudatum J.Agardh, 1841 accepted as Aglaothamnion caudatum (J.Agardh) Feldmann-Mazoyer, 1941
116. Species Callithamnion ceramicola (Lyngbye) Suhr, 1831 accepted as Erythrotrichia carnea (Dillwyn) J.Agardh, 1883 (synonym)
117. Species Callithamnion chadefaudii (L'Hardy-Halos) G.R.South & Tittley, 1986 accepted as Aglaothamnion chadefaudii L'Hardy-Halos, 1984
118. Species Callithamnion circinnatum Womersley, 1998 accepted as Aglaothamnion circinnatum (Womersley) Cormaci, G. Furnari & Alongi, 2023
119. Species Callithamnion cladodermum Zanardini, 1846 accepted as Balliella cladoderma (Zanardini) Athanasiadis, 1987
120. Species Callithamnion clandestinum Montagne, 1837 accepted as Acrochaetium clandestinum (Montagne) M.Howe, 1914
121. Species Callithamnion clavatum Schousboe ex C.Agardh, 1828 accepted as Monosporus pedicellatus (Smith) Solier, 1845
122. Species Callithamnion coccineum (Hudson) Lyngbye, 1819 accepted as Heterosiphonia plumosa (J.Ellis) Batters, 1902
123. Species Callithamnion codii P.Crouan & H.Crouan, 1860 accepted as Colaconema caespitosum (J.Agardh) Jackelman, Stegenga & J.J.Bolton, 1991 (synonym)
124. Species Callithamnion comosum Kützing, 1861 accepted as Monosporus pedicellatus (Smith) Solier, 1845
125. Species Callithamnion comosum Harvey, 1844 accepted as Warrenia comosa (Harvey) Harvey ex F.Schmitz & Hauptfleisch, 1897
126. Species Callithamnion confertum Womersley, 1998 accepted as Aglaothamnion confertum (Womersley) Cormaci, G. Furnari & Alongi, 2023
127. Species Callithamnion confusum J.Agardh, 1876 accepted as Pterothamnion confusum (J.Agardh) Athanasiadis, 1996
128. Species Callithamnion conspicuum (Sonder) Harvey, 1859 accepted as Spongoclonium conspicuum Sonder, 1855
129. Species Callithamnion constrictum Hering, 1846 accepted as Pleonosporium constrictum (Hering) Nägeli, 1862
130. Species Callithamnion corallina Ruprecht, 1850 accepted as Scagelia pylaisaei (Montagne) M.J.Wynne, 1985
131. Species Callithamnion corallina Lyngbye, 1819 accepted as Griffithsia corallinoides (Linnaeus) Trevisan, 1845 (synonym)
132. Species Callithamnion corallinoides (Linnaeus) Lyngbye, 1819 accepted as Griffithsia corallinoides (Linnaeus) Trevisan, 1845
133. Species Callithamnion corallinum Lyngbye, 1819 accepted as Griffithsia corallinoides (Linnaeus) Trevisan, 1845
134. Species Callithamnion cordatum Børgesen, 1909 accepted as Aglaothamnion cordatum (Børgesen) Feldmann-Mazoyer, 1941 (synonym)
135. Species Callithamnion corymbiferum (Kützing) Zanardini, 1847 accepted as Dasya corymbifera J.Agardh, 1841
136. Species Callithamnion corymbiferum (Kützing) Trevisan, 1845 accepted as Callithamnion corymbosum (Smith) Lyngbye, 1819
137. Species Callithamnion corynosporoides P.Crouan & H.Crouan, 1878 accepted as Rhodochorton corynosporoides (P.L.Crouan & H.M.Crouan) G.Hamel, 1927
138. Species Callithamnion crispellum C.Agardh, 1828 accepted as Heterosiphonia crispella (C.Agardh) M.J.Wynne, 1985
139. Species Callithamnion crouaniorum Kützing, 1849 accepted as Spermothamnion strictum (C.Agardh) Ardissone, 1883
140. Species Callithamnion cruciatum C.Agardh, 1827 accepted as Antithamnion cruciatum (C.Agardh) Nägeli, 1847 (synonym)
141. Species Callithamnion crustatum Schousboe, 1892 accepted as Rhodochorton purpureum (Lightfoot) Rosenvinge, 1900
142. Species Callithamnion cymosum Harvey, 1855 accepted as Spermothamnion cymosum (Harvey) De Toni, 1903
143. Species Callithamnion cystosirarum Ardissone, 1866 accepted as Acrochaetium secundatum (Lyngbye) Nägeli, 1858
144. Species Callithamnion dasycladum J.Agardh, 1841 accepted as Tetrathamnion myurum (Suhr) A.Athanasiadis, 1996
145. Species Callithamnion dasyoides J.Agardh, 1876 accepted as Pleonosporium squarrulosum (Harvey) I.A.Abbott, 1972
146. Species Callithamnion dasyurum Harvey, 1863 accepted as Dasythamniella dasyura (Harvey) Womersley, 1998
147. Species Callithamnion daviesii (Dillwyn) Lyngbye, 1819 accepted as Colaconema daviesii (Dillwyn) Stegenga, 1985 (synonym)
148. Species Callithamnion decipiens J.Agardh, 1842 accepted as Antithamnion decipiens (J.Agardh) Athanasiadis, 1996
149. Species Callithamnion decompositum J.Agardh, 1851 accepted as Compsothamnion decompositum (J.Agardh) Maggs & L'Hardy-Halos, 1993 (synonym)
150. Species Callithamnion delicatulum Harvey, 1855 accepted as Antithamnion delicatulum (Harvey) De Toni, 1903
151. Species Callithamnion densum Suhr, 1840 accepted as Antithamnion densum (Suhr) M.Howe, 1914
152. Species Callithamnion dimorphum Harvey, 1863 accepted as Antithamnion verticale (Harvey) J.Agardh, 1896
153. Species Callithamnion dispar Harvey, 1859 accepted as Elisiella dispar (Harvey) Womersely, 1998
154. Species Callithamnion divergens J.Agardh, 1876 accepted as Antithamnion delicatulum (Harvey) De Toni, 1903
155. Species Callithamnion dubium Zanardini, 1840 accepted as Antithamnion cruciatum (C.Agardh) Nägeli, 1847
156. Species Callithamnion dudresnayi (Bonnemaison) P.Crouan & H.Crouan, 1852 accepted as Gaillona seposita (Gunnerus) Athanasiadis, 2016
157. Species Callithamnion echigoense Noda, 1972 accepted as Aglaothamnion callophyllidicola (Yamada) Boo, I.K.Lee, Rueness & Yoshida, 1991 (synonym)
158. Species Callithamnion efflorescens J.Agardh, 1851 accepted as Grania efflorescens (J.Agardh) Kylin, 1944
159. Species Callithamnion elegans Schousboe ex C.Agardh, 1828 accepted as Gymnothamnion elegans (Schousboe ex C.Agardh) J.Agardh, 1892
160. Species Callithamnion elongatum Harvey, 1859 accepted as Anotrichium elongatum (Harvey) Baldock, 1976
161. Species Callithamnion endovagum Setchell & N.L.Gardner, 1924 accepted as Aglaothamnion endovagum (Setchell & N.L.Gardner) I.A.Abbott, 1972
162. Species Callithamnion entozoicum Reinsch, 1890 accepted as Rubrointrusa membranacea (Magnus) S.L.Clayden & G.W.Saunders, 2010
163. Species Callithamnion fasciculatum Harvey, 1833 accepted as Aglaothamnion fasciculatum (Harvey) Maggs & L'Hardy-Halos, 1993
164. Species Callithamnion fastigiatum Harvey, 1859 accepted as Leptoklonion fastigiatum (Harvey)Womersley, 1998
165. Species Callithamnion feldmanniae (Halos) G.R.South & Tittley accepted as Aglaothamnion feldmanniae Halos, 1965
166. Species Callithamnion felipponei Howe, 1931 accepted as Aglaothamnion felipponei (Howe) Aponte, Ballantine & J.N.Norris, 1994
167. Species Callithamnion flabelligerum Harvey, 1855 accepted as Anotrichium licmophorum (Harvey) Baldock, 1976
168. Species Callithamnion flaccidum Hooker f. & Harvey, 1845 accepted as Medeiothamnion flaccidum (J.D.Hooker & Harvey) J.F.Brauner, 1979
169. Species Callithamnion flagelliferum De Notaris, 1846 accepted as Spermothamnion repens var. flagelliferum (De Notaris) Feldmann-Mazoyer, 1941 (synonym)
170. Species Callithamnion flexuosum (C.Agardh) C.Agardh, 1828 accepted as Pleonosporium flexuosum (C.Agardh) Bornet, 1892 (synonym)
171. Species Callithamnion floccosum (O.F.Müller) C.Agardh, 1828 accepted as Antithamnionella floccosa (O.F.Müller) Whittick, 1980
172. Species Callithamnion floridulum (Dillwyn) Lyngbye, 1819 accepted as Rhodothamniella floridula (Dillwyn) Feldmann, 1978
173. Species Callithamnion fomosa Harvey, 1863 accepted as Hirsutithallia formosa (Harvey) Wollaston & Womersley, 1998
174. Species Callithamnion formosum Harvey, 1863 accepted as Hirsutithallia formosa (Harvey) Wollaston & Womersley, 1998
175. Species Callithamnion fragilissimum Zanardini, 1860 accepted as Antithamnion decipiens (J.Agardh) Athanasiadis, 1996
176. Species Callithamnion fruticulosum J.Agardh, 1841 (unaccepted)
177. Species Callithamnion furcellariae J.Agardh, 1851 (unaccepted, synonym)
178. Species Callithamnion gailloni (P.L.Crouan & H.M.Crouan) P.L.Crouan & H.M.Crouan, 1851 (unaccepted, synonym)
179. Species Callithamnion gallicum (Nägeli) Sauvageau, 1897 (unaccepted)
180. Species Callithamnion gorgoneum Montagne, 1857 (unaccepted)
181. Species Callithamnion gracilentum Harvey, 1855 (unaccepted)
182. Species Callithamnion gracillimum C.Agardh, 1828 (unaccepted, synonym)
183. Species Callithamnion graeffei Grunow, 1874 (unaccepted)
184. Species Callithamnion grande J.Agardh, 1842 (unaccepted)
185. Species Callithamnion grevillei Harvey, 1833 (unaccepted)
186. Species Callithamnion griffithsioides Sonder, 1855 (unaccepted, synonym)
187. Species Callithamnion griffithsioides (J.Agardh) Kylin, 1956 (unaccepted, synonym)
188. Species Callithamnion grunulatum (Duckluzeau) C. Agardh (unaccepted, misspelling)
189. Species Callithamnion halliae Collins, 1900 (unaccepted)
190. Species Callithamnion hanovioides Sonder, 1853 (unaccepted)
191. Species Callithamnion harveyanum J.Agardh, 1841 (unaccepted)
192. Species Callithamnion herveyi M.A.Howe, 1918 (unaccepted)
193. Species Callithamnion heteromorphum J.Agardh, 1876 (unaccepted)
194. Species Callithamnion hiemale Kjellman, 1907 (unaccepted)
195. Species Callithamnion hirtellum Zanardini, 1846 (unaccepted)
196. Species Callithamnion hirtum Hooker f. & Harvey, 1845 (unaccepted)
197. Species Callithamnion hookeri (Dillwyn) S.F.Gray, 1821 (unaccepted, synonym)
198. Species Callithamnion horizontale Harvey, 1855 (unaccepted)
199. Species Callithamnion hormocarpum Holmes, 1873 (unaccepted)
200. Species Callithamnion humile Kützing, 1849 (unaccepted)
201. Species Callithamnion imbricatum Schousboe ex Suhr, 1840 (unaccepted)
202. Species Callithamnion inordinatum Zanardini, 1846 (unaccepted, synonym)
203. Species Callithamnion interruptum (Smith) C.Agardh, 1828 (unaccepted)
204. Species Callithamnion investiens P.L.Crouan & H.M.Crouan, 1865 (unaccepted)
205. Species Callithamnion irregulare J.Agardh, 1841 (unaccepted)
206. Species Callithamnion lamourouxii (Nägeli) J.Agardh, 1851 (unaccepted, synonym)
207. Species Callithamnion lanceolatum (Derbès) Bertoloni, 1862 (unaccepted)
208. Species Callithamnion lanuginosum (Dillwyn) Lyngbye, 1819 (unaccepted)
209. Species Callithamnion lapponicum Ruprecht, 1850 (unaccepted)
210. Species Callithamnion laricinum Harvey, 1855 (unaccepted, synonym)
211. Species Callithamnion laterale Schousboe, 1892 (unaccepted)
212. Species Callithamnion latissimum Harvey, 1844 (unaccepted)
213. Species Callithamnion laxum Setchell & N.L.Gardner, 1903 (unaccepted, synonym)
214. Species Callithamnion lejolisea Farlow, 1877 (unaccepted)
215. Species Callithamnion lenormandii Suhr ex Kützing, 1849 (unaccepted)
216. Species Callithamnion lepadicola Welwitsch ex J.Agardh, 1876 (unaccepted)
217. Species Callithamnion leptocladum Montagne, 1842 (unaccepted)
218. Species Callithamnion levringii Lindauer, 1949 (unaccepted)
219. Species Callithamnion lherminieri P.Crouan & H.Crouan, 1878 (unaccepted)
220. Species Callithamnion licmophorum Harvey, 1859 (unaccepted)
221. Species Callithamnion luxurians J.Agardh ex Kützing, 1849 (unaccepted)
222. Species Callithamnion macropterum Meneghini ex Kützing, 1849 (unaccepted)
223. Species Callithamnion membranaceum Magnus, 1875 (unaccepted)
224. Species Callithamnion mesarthrocarpum Meneghini, 1844 (unaccepted)
225. Species Callithamnion mesocarpum Carmichael (unaccepted)
226. Species Callithamnion micropterum (Montagne) Montage, 1842 (unaccepted, synonym)
227. Species Callithamnion micropterum Hooker f. & Harvey, 1845 (unaccepted)
228. Species Callithamnion microptilum Grunow, 1867 (unaccepted)
229. Species Callithamnion microscopicum Nägeli ex Kützing, 1849 (unaccepted)
230. Species Callithamnion minimum Harvey, 1863 (unaccepted, synonym)
231. Species Callithamnion minutissimum Yamada, 1944 (unaccepted)
232. Species Callithamnion minutissimum Suhr ex Kützing, 1843 (unaccepted)
233. Species Callithamnion minutissimum Zanardini, 1841 (unaccepted)
234. Species Callithamnion minutum Suhr, 1831 (unaccepted)
235. Species Callithamnion mirabile (Suhr) Kützing, 1847 (unaccepted)
236. Species Callithamnion mucronatum J.Agardh, 1851 (unaccepted)
237. Species Callithamnion muelleri Sonder, 1855 (unaccepted)
238. Species Callithamnion multifidum (Hudson) Kützing, 1843 (unaccepted)
239. Species Callithamnion myurum Suhr, 1840 (unaccepted)
240. Species Callithamnion naccarianum Rudolphi, 1828 (unaccepted)
241. Species Callithamnion neglectum (Feldmann-Mazoyer) M.J.Wynne, 1986 (unaccepted)
242. Species Callithamnion nemalii De Notaris ex Dufour, 1863 (unaccepted, synonym)
243. Species Callithamnion nemalionis De Notaris ex L.Dufour, 1863 (unaccepted)
244. Species Callithamnion nodiferum J.Agardh, 1876 (unaccepted)
245. Species Callithamnion obstipum (Cowling, Kraft & J.A.West) Womersley, 1998 (unaccepted, synonym)
246. Species Callithamnion octosporum C.Agardh, 1828 (unaccepted)
247. Species Callithamnion oosumiense (Itono) Kajimura, 1990 (unaccepted)
248. Species Callithamnion oppositifolium J.Agardh, 1842 (unaccepted)
249. Species Callithamnion orbignianum Montagne, 1837 (unaccepted)
250. Species Callithamnion ovuligerum Askenasy, 1894 (unaccepted)
251. Species Callithamnion pallens Zanardini, 1846 (unaccepted)
252. Species Callithamnion paniculatum Schousboe, 1892 (unaccepted)
253. Species Callithamnion paradoxum Harvey, 1859 (unaccepted, synonym)
254. Species Callithamnion pectinatum Montagne, 1842 (unaccepted)
255. Species Callithamnion pedicellatum (Smith) S.F.Gray, 1821 (unaccepted)
256. Species Callithamnion pedunculatum P.L.Crouan & H.M.Crouan (unaccepted)
257. Species Callithamnion pedunculatum Kützing, 1843 (unaccepted, synonym)
258. Species Callithamnion pellucidum (Harvey) Hooker f. & Harvey, 1847 (unaccepted, synonym)
259. Species Callithamnion penicillatum Harvey, 1863 (unaccepted)
260. Species Callithamnion pluma (Dillwyn) C.Agardh, 1828 (unaccepted)
261. Species Callithamnion plumigerum Harvey, 1863 (unaccepted)
262. Species Callithamnion plumula (J.Ellis) Lyngbye, 1819 (unaccepted, synonym)
263. Species Callithamnion pollexfenii Harvey, 1844 (unaccepted)
264. Species Callithamnion polyacanthum Kützing, 1849 (unaccepted)
265. Species Callithamnion polyrhizum Harvey, 1863 (unaccepted)
266. Species Callithamnion polyspermum C.Agardh, 1828 (unaccepted)
267. Species Callithamnion posidoniae Zanardini, 1846 (unaccepted)
268. Species Callithamnion preissii Sonder, 1845 (unaccepted)
269. Species Callithamnion propebyssoides Womersley, 1998 (unaccepted)
270. Species Callithamnion pseudobyssoides P.Crouan & H.Crouan, 1867 (unaccepted, synonym)
271. Species Callithamnion ptilota Hooker f. & Harvey, 1845 (unaccepted)
272. Species Callithamnion pubes C.Agardh, 1828 (unaccepted)
273. Species Callithamnion pulchellum Harvey, 1855 (unaccepted)
274. Species Callithamnion pumilum Harvey, 1833 (unaccepted)
275. Species Callithamnion purpurascens (Hudson) S.F.Gray, 1821 (unaccepted, synonym)
276. Species Callithamnion purpureum (Lightfoot) Harvey, 1841 (unaccepted)
277. Species Callithamnion purpuriferum (Kützing) J.Agardh, 1851 (unaccepted)
278. Species Callithamnion pusillum Ruprecht, 1850 (unaccepted)
279. Species Callithamnion pusillum Harvey, 1855 (unaccepted)
280. Species Callithamnion pygmaeum Kützing, 1849 (unaccepted)
281. Species Callithamnion pylaisaei Montagne, 1837 (unaccepted)
282. Species Callithamnion pyramidatum Liebmann, 1839 (unaccepted)
283. Species Callithamnion rabenhorstii (Kützing) P.L.Crouan & H.M.Crouan, 1867 (unaccepted)
284. Species Callithamnion radicans Harvey, 1855 (unaccepted)
285. Species Callithamnion ramellosum Sonder, 1845 (unaccepted, synonym)
286. Species Callithamnion ramellosum (Kützing) Kützing, 1861 (unaccepted)
287. Species Callithamnion refractum Kützing, 1843 (unaccepted)
288. Species Callithamnion repens (Dillwyn) Lyngbye, 1819 (unaccepted)
289. Species Callithamnion rigidum E.Y.Dawson, 1962 (unaccepted)
290. Species Callithamnion roseolum (C.Agardh) C.Agardh, 1828 (unaccepted)
291. Species Callithamnion roseum (Roth) Lyngbye, 1819 (unaccepted, synonym)
292. Species Callithamnion rothii (Turton) Lyngbye, 1819 (unaccepted)
293. Species Callithamnion savianum Meneghini, 1840 (unaccepted, synonym)
294. Species Callithamnion scoparium Hooker f. & Harvey, 1845 (unaccepted)
295. Species Callithamnion scopula Harvey, 1855 (unaccepted, synonym)
296. Species Callithamnion scopulorum (C.Agardh) C.Agardh, 1828 (unaccepted, synonym)
297. Species Callithamnion secundatum (Lyngbye) C.Agardh, 1828 (unaccepted)
298. Species Callithamnion seirosperma (Harvey) Harvey (unaccepted)
299. Species Callithamnion seirospermum (Harvey) Griffiths, 1841 (unaccepted)
300. Species Callithamnion seminudum C.Agardh, 1827 (unaccepted)
301. Species Callithamnion semipennatum J.Agardh, 1842 (unaccepted)
302. Species Callithamnion sepositum (Gunnerus) P.S.Dixon & J.H.Price, 1981 (unaccepted, synonym)
303. Species Callithamnion serpens P.L.Crouan & H.M.Crouan, 1859 (unaccepted)
304. Species Callithamnion sertularioides Suhr, 1840 (unaccepted)
305. Species Callithamnion sessile Meneghini, 1844 (unaccepted)
306. Species Callithamnion shepherdii Womersley, 1998 (unaccepted)
307. Species Callithamnion simile Hooker f. & Harvey, 1845 (unaccepted)
308. Species Callithamnion simplex P.Crouan & H.Crouan, 1867 (unaccepted, synonym)
309. Species Callithamnion simpliciusculum Suhr, 1840 (unaccepted, synonym)
310. Species Callithamnion sparsum Harvey, 1833 (unaccepted)
311. Species Callithamnion sphaericum P.L.Crouan & H.M.Crouan ex J.Agardh, 1851 (unaccepted)
312. Species Callithamnion spiniferum Kylin, 1907 (unaccepted)
313. Species Callithamnion spinosum Harvey, 1833 (unaccepted)
314. Species Callithamnion spinulosum Suhr, 1840 (unaccepted)
315. Species Callithamnion spongiosum Harvey, 1833 (unaccepted, synonym)
316. Species Callithamnion squarrulosum Harvey, 1853 (unaccepted)
317. Species Callithamnion strictum C.Agardh, 1828 (unaccepted)
318. Species Callithamnion subnudum Ruprecht, 1850 (unaccepted, synonym)
319. Species Callithamnion subsimplex Harvey ex J.Agardh, 1876 (unaccepted)
320. Species Callithamnion subtilissimum Kützing, 1861 (unaccepted)
321. Species Callithamnion subulatum Harvey, 1862 (unaccepted)
322. Species Callithamnion subverticillatum Zanardini, 1840 (unaccepted)
323. Species Callithamnion superbiens Harvey, 1863 (unaccepted)
324. Species Callithamnion tenuissimum (Bonnemaison) Kützing, 1849 (unaccepted)
325. Species Callithamnion ternifolium Hooker f. & Harvey, 1845 (unaccepted)
326. Species Callithamnion thouarsii Montagne, 1837 (unaccepted)
327. Species Callithamnion thuioides (Smith) C.Agardh, 1828 (unaccepted)
328. Species Callithamnion thyrsigerum Thwaites ex Harvey, 1855 (unaccepted, synonym)
329. Species Callithamnion tingens Harvey, 1859 (unaccepted, synonym)
330. Species Callithamnion tingitana Schousboe ex Bornet, 1892 (unaccepted)
331. Species Callithamnion tripinnatum C.Agardh, 1828 (unaccepted, synonym)
332. Species Callithamnion truncatum Meneghini, 1844 (unaccepted)
333. Species Callithamnion turneri Sonder, 1881 (unaccepted)
334. Species Callithamnion turneri (Mertens ex Roth) C.Agardh, 1828 (unaccepted)
335. Species Callithamnion uncinatum E.Y.Dawson, 1962 (unaccepted)
336. Species Callithamnion uruguayense W.R.Taylor, 1939 (unaccepted)
337. Species Callithamnion vancouverianum J.Agardh, 1876 (unaccepted)
338. Species Callithamnion variabile C.Agardh, 1828 (unaccepted, synonym)
339. Species Callithamnion varispirale E.Y.Dawson, 1949 (unaccepted)
340. Species Callithamnion venustissimum Montagne, 1861 (unaccepted)
341. Species Callithamnion versicolor (C.Agardh) C.Agardh, 1828 (unaccepted)
342. Species Callithamnion verticale Harvey, 1855 (unaccepted)
343. Species Callithamnion verticillatum Suhr, 1840 (unaccepted)
344. Species Callithamnion violaceum Harvey, 1859 (unaccepted)
345. Species Callithamnion virgatulum Harvey, 1833 (unaccepted, synonym)
346. Species Callithamnion welwitschii J.Agardh, 1876 (unaccepted)
347. Species Callithamnion wollastonianum Harvey, 1855 (unaccepted)
348. Species Callithamnion acuminatum Schousboe (uncertain)
349. Species Callithamnion agardhianum Trevisan (uncertain)
350. Species Callithamnion alternatum Schousboe (uncertain)
351. Species Callithamnion amentaceum P.Crouan & H.Crouan (uncertain)
352. Species Callithamnion arachnoideum A.W.Griffiths ex Moore, 1837 (uncertain)
353. Species Callithamnion axillare Schousboe ex Suhr, 1840 (uncertain)
354. Species Callithamnion axirhizans Reinsch (uncertain)
355. Species Callithamnion batrachospermum Kützing (uncertain)
356. Species Callithamnion cabellae De Notaris (uncertain)
357. Species Callithamnion calcaratum De Notaris (uncertain)
358. Species Callithamnion corniculifructum P.Crouan & H.Crouan (uncertain)
359. Species Callithamnion crinale J.Agardh (uncertain)
360. Species Callithamnion cupressoides Meneghini (uncertain)
361. Species Callithamnion decussatum Meneghini ex Frauenfeld, 1855 (uncertain, uncertain taxonomic status subjected to verification)
362. Species Callithamnion dietziae Hooper ex Harvey (uncertain)
363. Species Callithamnion distichum Zanardini (uncertain)
364. Species Callithamnion divaricatum (Kützing) Trevisan, 1845 (uncertain, uncertain taxonomic status subjected to verification)
365. Species Callithamnion fallax P.Crouan & H.Crouan, 1867 (uncertain)
366. Species Callithamnion graniferum Meneghini, 1844 (uncertain, uncertain taxonomic status subjected to verification)
367. Species Callithamnion hapalidii P.Crouan & H.Crouan (uncertain)
368. Species Callithamnion hemiphorum J.Agardh (uncertain)
369. Species Callithamnion hemystachyon Schousboe (uncertain)
370. Species Callithamnion horridulum J.Agardh (uncertain)
371. Species Callithamnion labradorense Reinsch (uncertain)
372. Species Callithamnion lanosum Harvey, 1833 (uncertain)
373. Species Callithamnion laxatum Zanardini (uncertain)
374. Species Callithamnion microdendron Zanardini ex Frauenfeld, 1855 (uncertain, uncertain taxonomic status subjected to verification)
375. Species Callithamnion multifidum Harvey, 1855 (uncertain)
376. Species Callithamnion nanum Kützing (uncertain)
377. Species Callithamnion nigrescens J.Agardh (uncertain)
378. Species Callithamnion nodulosum Zanardini, 1840 (uncertain, uncertain taxonomic status subjected to verification)
379. Species Callithamnion ovale Schousboe (uncertain)
380. Species Callithamnion parvulum P.Crouan & H.Crouan, 1867 (uncertain)
381. Species Callithamnion pedicellatum H.Itono, 1971 (uncertain)
382. Species Callithamnion peregrinum Kützing (uncertain)
383. Species Callithamnion piliferum Kützing, 1861 (uncertain)
384. Species Callithamnion pteroton Schousboe (uncertain)
385. Species Callithamnion pulchellum C.Agardh, 1828 (uncertain, uncertain taxonomic status subjected to verification)
386. Species Callithamnion recurvatum Schousboe (uncertain)
387. Species Callithamnion rousselii Derbès & Solier, 1851 (uncertain, uncertain taxonomic status subjected to verification)
388. Species Callithamnion sandrianum Zanardini (uncertain)
389. Species Callithamnion siculum Ardissone (uncertain)
390. Species Callithamnion spinescens Kützing, 1843 (uncertain)
391. Species Callithamnion striatulum Suhr, 1840 (uncertain, uncertain taxonomic status subjected to verification)
392. Species Callithamnion subtile Kützing, 1849 (uncertain, uncertain taxonomic status subjected to verification)
393. Species Callithamnion utriculosum Kützing (uncertain)
394. Species Callithamnion ventricosum Kützing (uncertain)
395. Species Callithamnion vermilarae De Notaris (uncertain)
396. Species Callithamnion vidovichii Meneghini (uncertain)

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