Conferva percursa C.Agardh, 1817 accepted as Percursaria percursa (C.Agardh) Rosenvinge, 1893 (original description)
Diatoma biddulphiana (J.E. Smith) Agardh, 1817 (new combination reference)
Diatoma flocculosa var. tenuis (C.Agardh) C.Agardh, 1817 accepted as Diatoma tenue C. Agardh, 1812 (new combination reference)
Diatoma obliquata (J.E.Smith) C.A.Agardh (new combination reference)
Diatoma pectinalis (O. Müller) Agardh, 1812 (original description)
Diatoma stipitata (J.E. Smith) Agardh, 1817 (new combination reference)
Diatoma taeniaeformis (E.B.) Agardh, 1817 (new combination reference)
Frustulia viridis Agardh, 1817 (original description)
Gloionema chthonoplastes Agardh, 1817 (original description)
Gloionema foetidum (Dillwyn) Agardh, 1817 (new combination reference)
Griffithsia C.Agardh, 1817 (original description)
Griffithsia barbata C.Agardh, 1817 accepted as Anotrichium barbatum (C.Agardh) Nägeli, 1862 (original description)
Griffithsia corallina C.Agardh, 1817 accepted as Griffithsia corallinoides (Linnaeus) Trevisan, 1845 (original description)
Hutchinsia C.Agardh, 1817 (original description)
Hutchinsia aculeata C.Agardh, 1817 accepted as Leptosiphonia fibrillosa (Agardh) Savoie & G.W.Saunders, 2019 (original description)
Hutchinsia divaricata C.Agardh, 1817 accepted as Leptosiphonia fibrillosa (Agardh) Savoie & G.W.Saunders, 2019 (original description)
Hutchinsia fibrillosa C.Agardh, 1817 accepted as Leptosiphonia fibrillosa (Agardh) Savoie & G.W.Saunders, 2019 (original description)
Ptilota C.Agardh, 1817 (original description)
Ptilota plumosa C.Agardh, 1817 accepted as Ptilota gunneri P.C.Silva, Maggs & L.M.Irvine, 1993 (original description)
Rytiphlaea C.Agardh, 1817 (original description)
Rytiphlaea pinastroides C.Agardh, 1817 accepted as Halopithys incurva (Hudson) Batters, 1902 (original description)
Rytiphlaea purpurea C.Agardh, 1817 accepted as Rytiphlaea tinctoria (Clemente) C.Agardh, 1824 (original description)
Ulva paradoxa C.Agardh, 1817 (original description)