TRANSFER OF CARPOPELTIS-FORMOSANA OKAMURA TO PRIONITIS (HALYMENIACEAE, HALYMENIALES)

The vegetative and reproductive anatomy of Carpopeltis formosana Okamu ra is described and illustrated from material collected in Vietnam and Taiwan. Although superficially similar to Carpopeltis, C. formosana w as found to be more like Prionitis in the following features: 1. The m edullary layer is thick and occupies more than one third of the thallu s: 2. numerous proliferations are produced from the thallus margins an d surfaces; 3. reproductive structures are confined to the apical segm ents and/or to the proliferations and 4. auxiliary-cell ampullae are s imple and branched only to the second order. Carpopeltis formosana is therefore considered to belong in Prionitis. Carpopeltis formosana has been considered to be closely related to Prionitis angusta (Okamura) Okamura [formerly Carpopeltis angusta (Okamura) Okamura], and the two entities were therefore compared. They were found to be clearly separa ble from each other in thallus size and shape in section, and in tetra sporangial formation. Carpopeltis formosana is therefore concluded to be a distinct species and the name Prionitis formosana (Okamura) Kawag uchi et Nguyen comb. nov. is proposed.