Ottia meiospora (Ottiaceae, Rhodophyta), a new genus and family endophytic within the thallus of Nothocladus (Batrachospermales, Rhodophyta).

A new genus, Ottia, and family, Ottiaceae, are proposed within the Acrochaetiales to accommodate the uniseriate red algal endophyte of batrachspermalean taxa previously named Balbiania meiospora. Prior to this study, Balbiania investiens was transferred to its own family and order (Balbianiales) based on comparative DNA sequence data and a distinctive reproductive morphology. However, the second species described in this genus, B. meiospora, continued to be treated as a species of Audouinella (A. meiospora) pending further investigation. Phylogenetic analyses of sequence data confirmed only a distant relationship between the two endophytes, and a closer alliance of B. meiospora to Acrochaetiales. The data also showed that Ottia meiospora was the deepest diverging lineage in the Acrochaetiales, sister to all of the currently recognized genera and families. In this study, we review the classification of what we now call O. meiospora - reported from Australia, New Zealand and Brazil - based on sequence and morphological data. Morphological observations provided little clarity around the reproductive morphology or the life cycle of this endophyte of Nothocladus s. lat. found commonly in mainland Australia but, to date, less so in New Zealand.

SYSTEMATICS OF THE BATRACHOSPERMALES (RHODOPHYTA)-A SYNTHESIS(1).

Recent molecular and morphological data necessitate a major taxonomic revision of the Batrachospermales, an order of red algae, distributed in freshwater habitats throughout the world. This article is a synthesis of available information with some targeted additional sequence data, resulting in a few relatively conservative taxonomic changes to begin the process of creating a natural taxonomy for the Batrachospermales. To increase the information content of our taxonomic categories, and in particular to reduce paraphyly, we describe one new genus (Kumanoa) and a new section in Batrachospermum (section Macrospora), and we amend the circumscriptions of the family Batrachospermaceae (to include Lemaneaceae and Psilosiphonaceae), the genus Batrachospermum (to exclude the sections Contorta and Hybrida, raised to genus level as Kumanoa), and the sections Aristata, Helminthoidea, and Batrachospermum of Batrachospermum. We also provide a new name, B. montagnei, for the illegitimate B. guyanense, and recognize an informal paraphyletic grouping of taxa within Batrachospermum, the "Australasica Group." This taxonomic synthesis increases the level of monophyly within the Batrachospermales but minimizes taxonomic change where data are still inadequate.