OF SOUTH AUSTRALIA. 
267 
II.— DICHOTOMAE. 
Total frond pellucidly articulate, subdichotomous, branched. Hamuli 
tetrasiphonous. 
Polysiphonia Roeana Harvey. • 
Harv. Phyc. Aus. t. 35; De Toni Syll. Alg. IV., 877. 
Fronds tufted, 7 cm. to 15 cm., long, very fine, excessively and very 
irregularly branched; primary divisions dichotomous with frequent sup- 
pression of one arm of the fork, becoming irregularly zig-zag; secondary 
branches either alternate or very commonly secund, repeatedly com- 
pounded; lesser branches tapering gradually to a point. Articulations 
pellucid in all parts, composed of four tubes surrounding a minute cavity ; 
the lower several times as long as broad, the upper gradually shorter, 
ultimate ones scarcely longer than broad. Colour brilliant rosy-red, well 
preserved on drying; adheres to paper. Substance soft and very flaccid, 
but not gelatinous ; does not rapidly decompose in fresh water. 
Dredged off Fremantle, West Australia. 
Polysiphonia mollis Hooker et Harvey. 
Harv. Nereis Austral, p. 43; De Toni Syll. Alg. IV., 877. 
Fronds' erect, solitary or approximating, but scarcely tufted, to 15 cm. 
high, setaceous at the base, then capillary, and exceedingly slender above, 
much branched. Primary stem subdichotomous, but soon lost in the 
excessive division of the branches and ramuli, which are again and again 
decompounded in an irregularly dichotomous manner; the ultimate ramuli 
simple, elongate and erecto-patent, fibrilliferous. Articulations in the lower 
part very short, those of the principle divisions twice as long as broad, 
those of the smaller branches gradually shorter. Stem tetrasiphonous. 
Tetraspores borne in series in apices of distorted flexuose ramuli. Cysto- 
carps very numerous, minute, shortly stalked, ovate, acute. 
South Australia (Encounter Bay, Eastern Bays, North Coast of Kangaroo 
Island), Tasmania, Western Australia. 
Polysiphonia succulenta Harvey. 
Harv. FI. Tasm. p. 300; De Toni Syll. Alg. IV., 879. 
Frond ultrasetaceous, gelatinose-cartilaginous, to 15 cm. high; much 
branched dichotomously from the base. Tetrasiphonous, articulate, the 
articulations below three times as long as broad, ultimately as long as 
broad. Tetraspores in dense fasciculato-multifid terminal ramuli. Cysto- 
carps numerous, shortly stalked, ovate. This species resembles a large and 
coarsely grown P. mollis , but the frond is much more robust and succulent, 
and the branching more regularly dichotomous. 
South Australia (American River, Kangaroo Island), Tasmania, Victoria. 
Polysiphonia abscissa Hooker et Harvey. 
Syn. P. microcarjm H. and H. 
Harv. in Lond. Journ. Bot. IV., p. 266; Harv. Nereis Austral, p. 43- 
De Toni Syll, Alg. IV., 879. 
Fronds 6 cm. to 10 cm. long, ovate in outline, membranaceous-gelatinous, 
flaccid, tenaceous. Primary stem sparingly divided, flexuose, emitting 
