Descriptions of Two New Genera, Scageliopsis and Glandothamnus (Ceramiaceae, Rhodophyta), Including Five Previously Undescribed Species from Southern Australia

Abstract

Two genera, Scageliopsis and Glandothamnus, including 5 new species (Scageliopsis patens, Glandothamnus ramulentus, G. manifestus, G. flexilis, and G. acicularis), are described from southern Australia. Both genera have some similarities with the northern hemisphere genus Scagelia Wollaston and with Platythamnion J. Agardh. Scageliopsis is characterized by whorls of equal whorl-branchlets, lateral gland cells, and carposporophytes produced on basal cells of fully developed whorl-branchlets which arise from axes capable of continued elongation. Glandothamnus is distinguished by unilateral initiation of whorl-branchlets at branch apices, adaxial branching of young whorl-branchlets, mature gland cells elongated obliquely to whorl-branchlet axes, and carposporophytes borne on fully formed whorl-branchlets arising from axes which only occasionally continue to elongate. Scageliopsis and Glandothamnus are placed with Scagelia in the tribe Antithamnieae (Ceramiaceae). Complete keys to all known genera of the tribes Antithamnieae and Heterothamnieae are included.