Athanasiadis, A. & Kraft, G.T., 1994
Athanasiadis, A. & Kraft, G.T. (1994). Description of Pterothamnion squarrulosum (Harvey) comb. nov. from south-eastern Australia and southern New Zealand, with a taxonomic re-assessment of the genera Pterothamnion, Platythamnion and Glandothamnus (Ceramiaceae, Rhodophyta). European Journal of Phycology 29: 119-133, 27 figs, 1 table.
We describe Pterothamnion squarrulosum (Harvey) Athanasiadis et Kraft, comb. nov., from south-eastern Australia and southern New Zealand, and discuss the relationships of this, the largest and most densely branched species in the genus, to other Australasian representatives. Comparative studies of the type and other species of the genera Pterothamnion, Platythamnion and Glandothamnus support the recognition of a single genus, Pterothamnion, encompassing at least 27 species from warm- to cold-temperate regions of the world. Features such as procarp numbers, the sizes, shapes and positions of gland cells, and the developmental patterns and organisation of determinate (whorl-) branches show considerable variation within even single species and cannot be considered as diagnostic characters at the genus level in this complex. An emended description of Pterothamnion is proposed.