We conducted phylogenetic analyses of plastid rbcL sequences and detailed observations on female reproductive structures of foliose halymeniacean red algae collected in Chile and Peru. We describe Ramirezia osornoensis gen. et. sp. nov., characterised by having seven-celled carpogonial branches and six-celled auxiliary-cell branches, formation of primary connecting filaments after fertilisation, nutritive filaments mostly upwardly directed and welldeveloped pericarps. It was distributed from central Chile to the Falkland Islands. The female structures of Halymenia lapathifolia Kützing and its placement in the rbcL tree indicated that it belonged to a new genus, which we named Ramirezia. In the rbcL phylogeny, Ramirezia consistently formed a clade with Chilean/Peruvian species. We described Phyllymenia acletoi sp. nov. on the basis of specimens from Peru. Phyllymenia acletoi had a distinctive rbcL phylogeny and Phyllymenia-type female structures. It was characterised by thalli divided into several lobes, a loose cortex of five to seven layers of cells with stellate inner cortical cells, a gradual transition from cortex to lax medulla and pericarps with few involucral filaments. © 2014 International Phycological Society.