TYPIFICATION OF THE AUSTRALASIAN BROWN ALGA ZONARIA-TURNERIANA AGARDH,J. (DICTYOTALES) AND DESCRIPTION OF THE ENDEMIC NEW-ZEALAND SPECIES, ZONARIA-AUREOMARGINATA SP. NOV

There are two species of Zonaria in New Zealand, instead of one highly variable species as previously thought. Zonaria turneriana was descri bed by J. Agardh (1870) in a paper dealing with algae from the Chatham Islands, New Zealand. The type specimen was not cited in the descript ion, which refers generally to collections of Z. turneriana from New Z ealand and Australia. Subsequently, two lectotypes have been designate d, one from the South Island and the other from the Chatham Islands, b ut neither are considered to be appropriate. A specimen from Turner's herbarium, which would have been available to J. Agardh when he descri bed the species, is selected as the lectotype of Z. turneriana. The ne w species, Zonaria aureomarginata, is described. Zonaria aureomarginat a and Z. turneriana are similar in morphology, sporangial and gametang ial structure but they differ markedly in vegetative anatomy. Unlike Z . turneriana and every other species of Zonaria, the medullary cells o f Z. aureomarginata vary greatly in size and are not always aligned in regular rows. In transverse section, one to four (Z. aureomarginata) instead of one to two cortical cells (Z. turneriana) occupy the width of a medullary cell. Zonaria aureomarginata is found only on the North Island, the Marlborough region of the South Island, the Chatham and T hree Kings Islands, New Zealand. The biogeographic affinities of the t en species of Zonaria are discussed.