| Major Group | Scientific Name | Year | Name Status | Native Status |
| Chlorophyceae (green) | Acrosiphonia coalita | 1986 | accepted name | Native |
| Phaeophyceae (brown) | Acinetospora nicholsoniae | 1971 | accepted name | Cryptogenic |
| Phaeophyceae (brown) | Adenocystis californica
(Under Coilodesme californica) | 1850 | homotypic synonym | |
| Phaeophyceae (brown) | Agarum costatum
(Under Costaria costata) | 1828 | homotypic synonym | |
| Phaeophyceae (brown) | Agarum fimbriatum | 1862 | accepted name | Native |
| Phaeophyceae (brown) | Alaria curtipes
(Under Alaria marginata) | 1901 | heterotypic synonym | |
| Phaeophyceae (brown) | Alaria fragilis f. bullata
(Under Alaria marginata) | 1901 | heterotypic synonym | |
| Phaeophyceae (brown) | Alaria marginata | 1840 | accepted name | Native |
| Phaeophyceae (brown) | Alaria marginata f. nana
(Under Alaria marginata) | 1913 | heterotypic synonym | |
| Phaeophyceae (brown) | Alaria marginata var. musiformis
(Under Alaria marginata) | 1840 | heterotypic synonym | |
| Phaeophyceae (brown) | Alaria nana
(Under Alaria marginata) | 1903 | heterotypic synonym | |
| Phaeophyceae (brown) | Alaria taeniata
(Under Alaria marginata) | 1889 | heterotypic synonym | |
| Phaeophyceae (brown) | Alaria tenuifolia
(Under Alaria marginata) | 1903 | heterotypic synonym | |
| Phaeophyceae (brown) | Alaria tenuifolia f. amplior
(Under Alaria marginata) | 1903 | heterotypic synonym | |
| Phaeophyceae (brown) | Alaria valida
(Under Alaria marginata) | 1903 | heterotypic synonym | |
| Phaeophyceae (brown) | Alaria valida f. longipes
(Under Alaria marginata) | 1903 | heterotypic synonym | |
| Phaeophyceae (brown) | Ascophylla fastigiata
(Under Silvetia compressa) | 1891 | heterotypic synonym | |
| Phaeophyceae (brown) | Asperococcus cancellatus
(Under Hydroclathrus clathratus) | 1846 | homotypic synonym | |
| Phaeophyceae (brown) | Asperococcus clathratus
(Under Hydroclathrus clathratus) | 1848 | homotypic synonym | |
| Phaeophyceae (brown) | Asperococcus sinuosus
(Under Colpomenia sinuosa) | 1832 | homotypic synonym | |
| Phaeophyceae (brown) | Asperococcus ulvoides
(Under Soranthera ulvoidea) | 1850 | homotypic synonym | |
| Rhodophyceae (red) | Acanthocladia muricata
(Under Endocladia muricata) | 1851 | homotypic synonym | |
| Rhodophyceae (red) | Acrosorium ciliolatum | 1924 | accepted name | Native |
| Rhodophyceae (red) | Acrosorium uncinatum
(Under Acrosorium ciliolatum) | 1924 | heterotypic synonym | |
| Rhodophyceae (red) | Acrosorium uncinatum var. venulosum
(Under Acrosorium ciliolatum) | 1984 | heterotypic synonym | |
| Rhodophyceae (red) | Acrosorium venulosum
(Under Acrosorium ciliolatum) | 1924 | heterotypic synonym | |
| Rhodophyceae (red) | Actinococcus chiton
(Under Fredericqia chiton) | 1914 | homotypic synonym | |
| Rhodophyceae (red) | Agardhiella coulteri
(Under Sarcodiotheca gaudichaudii) | 1897 | heterotypic synonym | |
| Rhodophyceae (red) | Agardhiella gaudichaudii
(Under Sarcodiotheca gaudichaudii) | 1979 | homotypic synonym | |
| Rhodophyceae (red) | Aglaophyllum ciliolatum
(Under Acrosorium ciliolatum) | 1869 | homotypic synonym | |
| Rhodophyceae (red) | Ahnfeltia fastigiata | 1970 | accepted name | Native |
| Rhodophyceae (red) | Ahnfeltia gigartinoides | 1847 | misapplied; not in California | |
| Rhodophyceae (red) | Ahnfeltia plicata | 1835 | misapplied; not in California | |
| Rhodophyceae (red) | Ahnfeltia plicata var. fastigiata
(Under Ahnfeltia fastigiata) | 1853 | homotypic synonym | |
| Rhodophyceae (red) | Ahnfeltiopsis gigartinoides | 1992 | misapplied; not in California | |
| Rhodophyceae (red) | Ahnfeltiopsis leptophylla
(Under Besa leptophylla) | 1992 | homotypic synonym | |
| Rhodophyceae (red) | Ahnfeltiopsis linearis | 1992 | accepted name | Native |
| Rhodophyceae (red) | Amphiroa algeriensis
(Under Amphiroa beauvoisii) | 1857 | heterotypic synonym | |
| Rhodophyceae (red) | Amphiroa aspergillum
(Under Lithothrix aspergillum) | 1891 | homotypic synonym | |
| Rhodophyceae (red) | Amphiroa aspergillum f. nana
(Under Lithothrix aspergillum) | 1903 | heterotypic synonym | |
| Rhodophyceae (red) | Amphiroa beauvoisii | 1816 | accepted name | Native |
| Rhodophyceae (red) | Amphiroa californica
(Under Bossiella californica) | 1842 | homotypic synonym | |
| Rhodophyceae (red) | Amphiroa complanata
(Under Amphiroa beauvoisii) | 1843 | heterotypic synonym | |
| Rhodophyceae (red) | Amphiroa compressa var. tenuis
(Under Amphiroa beauvoisii) | 1945 | heterotypic synonym | |
| Rhodophyceae (red) | Amphiroa drouetii
(Under Amphiroa beauvoisii) | 1953 | heterotypic synonym | |
| Rhodophyceae (red) | Amphiroa dubia
(Under Amphiroa beauvoisii) | 1858 | heterotypic synonym | |
| Rhodophyceae (red) | Amphiroa epiphlegnoides
(Under Calliarthron tuberculosum) | 1862 | heterotypic synonym | |
| Rhodophyceae (red) | Amphiroa franciscana var. robusta
(Under Amphiroa beauvoisii) | 1953 | heterotypic synonym | |
| Rhodophyceae (red) | Amphiroa linearis
(Under Amphiroa beauvoisii) | 1858 | heterotypic synonym | |
| Rhodophyceae (red) | Amphiroa mexicana
(Under Amphiroa beauvoisii) | 1945 | heterotypic synonym | |
| Rhodophyceae (red) | Amphiroa parthenopea
(Under Amphiroa beauvoisii) | 1841 | heterotypic synonym | |
| Rhodophyceae (red) | Amphiroa peninsularis
(Under Amphiroa beauvoisii) | 1945 | heterotypic synonym | |
| Rhodophyceae (red) | Amphiroa polysona
(Under Amphiroa beauvoisii) | 1849 | heterotypic synonym | |
| Rhodophyceae (red) | Amphiroa polyzona
(Under Amphiroa beauvoisii) | 1846 | heterotypic synonym | |
| Rhodophyceae (red) | Amphiroa pustulata
(Under Amphiroa beauvoisii) | 1836 | heterotypic synonym | |
| Rhodophyceae (red) | Amphiroa tuberculosa
(Under Calliarthron tuberculosum) | 1843 | homotypic synonym | |
| Rhodophyceae (red) | Amphiroa tuberculosa
(Under Calliarthron tuberculosum) | 1902 | heterotypic synonym | |
| Rhodophyceae (red) | Amphiroa tuberculosa f. californica
(Under Bossiella californica) | 1903 | homotypic synonym | |
| Rhodophyceae (red) | Amphiroa vertebralis
(Under Calliarthron tuberculosum) | 1842 | heterotypic synonym | |
| Rhodophyceae (red) | Amphiroa zonata
(Under Amphiroa beauvoisii) | 1902 | heterotypic synonym | |
| Rhodophyceae (red) | Amplisiphonia pacifica | 1939 | accepted name | Native |
| Rhodophyceae (red) | Analipus japonicus | 1971 | accepted name | Native |
| Rhodophyceae (red) | Antithamnion floccosum f. pacificum
(Under Antithamnionella pacifica) | 1903 | homotypic synonym | |
| Rhodophyceae (red) | Antithamnion pacificum
(Under Antithamnionella pacifica) | 1925 | homotypic synonym | |
| Rhodophyceae (red) | Antithamnion uncinatum
(Under Antithamnionella pacifica) | 1927 | homotypic synonym | |
| Rhodophyceae (red) | Antithamnionella pacifica | 1972 | accepted name | Native |
| Rhodophyceae (red) | Antithamnionella pacifica var. uncinata
(Under Antithamnionella pacifica) | 1972 | homotypic synonym | |
| Rhodophyceae (red) | Apoglossum decipiens
(Under Cumathamnion decipiens) | 1898 | homotypic synonym | |
| Rhodophyceae (red) | Apona californica
(Under Ceramium californicum) | 1898 | homotypic synonym | |
| Rhodophyceae (red) | Arthrocardia epiphlegnoides
(Under Calliarthron tuberculosum) | 1904 | heterotypic synonym | |
| Rhodophyceae (red) | Arthrocardia silvae
(Under Chiharaea silvae) | 1971 | homotypic synonym | |
| Rhodophyceae (red) | Arthrocardia tuberculosa
(Under Calliarthron tuberculosum) | 1904 | homotypic synonym | |
| Rhodophyceae (red) | Arthrocardia vertebralis
(Under Calliarthron tuberculosum) | 1904 | heterotypic synonym | |
| Rhodophyceae (red) | Asparagopsis delilei
(Under Asparagopsis taxiformis) | 1841 | homotypic synonym | |
| Rhodophyceae (red) | Asparagopsis sanfordiana
(Under Asparagopsis taxiformis) | 1855 | heterotypic synonym | |
| Rhodophyceae (red) | Asparagopsis taxiformis | 1845 | accepted name | Native |
