The marine algae are plants of considerable biological and economic importance. The Nemaliales, one of the most diverse and significant orders of red algae in Australian waters, is found on shores, in rockpools and in the subtidal on all coasts of Australia. These beautiful and unusual plants offer a spectacular range of form and colour some are relatively firm and chalky, others are worm-like or are highly mucilaginous and have the consistency of jelly. This volume is richly illustrated with colour photographs and line drawings, and documents the three families, 20 genera and 56 species of Australian Nemaliales. A detailed introduction to the history, structure, reproduction and relationships of the order is followed by advice on the microscopical examination of specimens, identification keys to families, genera and species and comprehensive descriptions of each taxon. Appendices include the description of the new genus Titanophycus and DNA sequence analyses of the evolutionary relationships of the order.