Studies on southern Australian taxa of Solieriaceae, Rhobdoniaceae and Rhodophyllidaceae (Rhodophyta)

Abstract

The morphology, reproduction, and relationships of the southern Australian species of three closely related families of the Gigartinales (Solieriaceae, Rhabdoniaceae and Rhodophyllidaceae) are described.

In the multiaxial Solieriaceae, most genera of which are non-Australian, Solieria robusta (Greville) Kylin and five species of Callophycus Trevisan have been studied. Apart from Sarconema filiforme (Sonder) Kylin, these are the only southern Australian taxa retained in the family.

In the uniaxial and non-procarpic Rhabdoniaceae, Rhabdonia Hooker and Harvey (three species), Catenella nipae Zanardini, Areschougia Harvey (three species), and Erythroclonium Sonder (four species) have been studied. A species previously placed in Areschougia, A. dumosa Harvey, is found to be procarpic and is described as a new genus, Melanema. In all other vegetative and reproductive features it is similar to Areschougia, and it is provisionally retained in the Rhabdoniaceae.

In the uniaxial and procarpic Rhodophyllidaceae the following are studied: Rhodophyllis Kuetzing (four species), Craspedocarpus Schmitz (four species, previously placed in Rhodophyllis), Gloiophyllis barkeriae (Harvey) J . Agardh, Calliblepharis planicaulis (Harvey) Kylin, and a new genus Austroclonium, based on Rhabdonia charoides Harvey.

The main features used by Kylin in separating and characterizing these families and genera are considered generally satisfactory, but there appear to be cases where they cannot be rigidly applied. Such cases include the direction of gonimoblast development, and in the case of Melanema it is suggested that procarpy has arisen, by loss of ability to form connecting filament, from a non- procarpic ancestor such as Areschougia.