Halymenia a genus of a macroscopic red algae that grows in oceans worldwide. It includes the following species: * Halymenia abyssicola E.Y.Dawson * Halymenia actinophysa M.A.Howe * Halymenia angusta (J.Agardh) De Toni * Halymenia asymmetrica Gargiulo, de Masi & Tripodi * Halymenia bifida E.Y.Dawson * Halymenia brasiliana S.M.P.B.Guimarães & M.T.Fujii * Halymenia californica G.M.Smith & Hollenberg * Halymenia carnosa * Halymenia cerratei C.O.Acleto * Halymenia chiangiana I.A.Abbott & Kraft * Halymenia clathrata E.C.Oliveira, Pinheiro-Vieira & R.E.Norris * Halymenia cromwellii I.A.Abbott * Halymenia curvicornis J.Agardh * Halymenia dilatata Zanardini * Halymenia dubia Bory de Saint-Vincent * Halymenia duchassaingii (J.Agardh) Kylin * Halymenia durvillei Bory de Saint-Vincent