OF SOUTH AUSTRALIA. 
263 
vary greatly in general appearance; some 'are of large size, very robust 
and shrubby, rigid and cartilaginous; others are exceedingly flaccid and 
slender, membranaceous or gelatinous. In colour they vary from crimson 
through purple and brownish red to brown. The greater number of species 
are epiphytic, a few being parasitic, They grow on varied substrata, some- 
times typical for a particular species; there may be rocks, stones, shells, 
wood, or most commonly, other algae. 
From the original genus Polysiphonia, groups of species have been 
removed to form new genera, together, in many cases, with other species. 
At the end of the genus Polysiphonia as here given will be found a list of 
the species hitherto placed in Polysiphonia, and now removed to other 
genera. This- arrangement follows De Toni. The genus was divided by 
J. G. Agardh into two large subgenera ; Oligosiphonia, in which the number 
of primary siphons is four, or rarely five; and Polysiphonia , in which the 
number is six or higher. This division is followed here, and the subgenera 
further divided as given by Harvey in his “Nereis Australis/’ retaining 
only the groups to which our Australian species belong. 
Below are described all the species which have been recorded from the 
South-western, Southern, and Eastern coasts of Australia, and Tasmania. 
Only a very few species have been recorded from Northern Australia. 
Many of the forms described have only been recorded once or twice, and 
the descriptions of many are unsatisfactory. The pressing need of the 
present time is for extensive collecting in many localities, and careful iden- 
tification from both descriptions and figures and authentic herbarium 
specimens. This, unfortunately, is far from easy. Many of the descriptions 
are in Latin, and often unavailable ; figures, the main essential, are 
frequently not given with original descriptions; and type or authentic 
specimens are often not available. However, it is hoped that this com- 
pilation of all Australian records of this genus will be of help to Australian 
students of the algae, for the field for work on these groups is unlimited. 
The main references to each species have been given. These, whenever 
possible, include one to a figure of the particular species, for in many cases 
identification is impossible with descriptions alone. 
Subgenus Oligosiphonia. 
Siphons primarily four, rarely five. 
I.— ELONGATAE. 
Fronds opaque, inarticulate. Kamuli articulate, tetrasiphonous. 
Polysiphonia Hookeri Harvey. 
Harv. Nereis Austral, p. 40, t. XII. ; De Toni, Syll. Alg. IV., 905. 
Frond 30 >cm. to 60 cm. long or more, cartilaginous, about 1 mm. in 
diameter below, gradually attenuated upwards ; pinnated with patent 
branches, much slenderer than the main stem, which gradually diminishes 
in length towards the apex, giving the frond an ovate outline. Branches 
once or twice pinnated ; branches, pinnae and pinnulae tapering to the base, 
inarticulate, closely beset with minute subquadrifarous ramuli, subsimple 
or forked in younger specimens, terminating in capillary, dichotomous, 
