Abstract
Thirty-two species, representing 11 tribes of Ceramiaceae, are recognized from collections made by G.F. Papenfuss and R.F. Scagel on the International Indian Ocean Expedition of 1962. Most species are recorded from the east coast of Africa between latitudes 4°8(southern Kenya) and 34°8 (southern South Africa), but three species are included from northern Madagascar and three from Western Australia. One new species, Ptilothamnion polysporum, is described and a specimen of Balliella subcorticata (Itono) Itono & Tanaka from central Mozambique extends the known distribution of this species. Recognition of a transition zone near the South Africa-Mozambique border is upheld.