Betaphycus Doty, gen. nov. Cell walls containing a predominance of b-carrageenan; fronds cylindrical to flattened, with axis a compressed core of rhizoids; base crustose; tetrasporangia seriately divided, borne in spindle-shaped to lanceolate cortical proliferations.
Parietes cellularum pro parte majore e ``b-carrageenan'' continentes; frondes cylindricae vel compressae, cum medullam compressam rhizoideorum; basis crustosis; tetrasporangia seriatim divisa, in prolificationibus corticalibus fusiformibus vel lanceolatis.
Type species: Betaphycus philippinense Doty.
Betaphycus, like Kappaphycus Doty (1988: 171), has been segregated from Eucheuma J. Agardh (1847: 16). The three genera are commercial sources of carrageenan, and, while more than one type is usually found in any particular species, a predominance of b-carrageenan is found in Betaphycus, a predominance of k-carrageenan is found in Kappaphycus, while a predominance of i-carrageenan is found in Eucheuma.
The concept of Betaphycus was proposed by Doty (1995: 237), but the generic name was not validly published since a Latin diagnosis was not provided. This requirement (Art. 36.2) is fulfilled herein. The name of the type species is validated by reference to the Latin description and illustrations provided previously (Doty, 1995: 237, figs. 1--5). The holotype is BISH 636-903 (Doty 33052) from eastern Sorsogon Province, Philippines. Combinations to provide names for the other two species in the genus are validated in the main catalogue.