OF SOUTH AUSTRALIA. 
353 
upper part of the frond, sessile, rarely pedicellate, cruciate or transversely 
divided. Antheridia pedicellate, furcate, in the same position as the tetra- 
spores, thyrsoid. 
South Coast of Australia, Tasmania, New Zealand, Atlantic, Mediter- 
ranean, Cape Horn. 
Antithamnion nodiferum J. Agardh. 
= Callithamnion nodiferum J. Agardh = Callithamnion simile 
Harvey pars. 
Frond subsolitary, robust, rigid, much branched ; branches alternately 
decompound, articulated, ecorticate, at length hirsute, oppositely pinnate 
at every joint; pinnae minute, horizontally patent or recurved, pectinated 
above, more or less secundly compound; tips of ramuli acute. 
Attachment discoid, afterwards a conical mass coated with curled fibres. 
Fronds erect 2 cm. to 14 cm. high, solitary or few together, distichously 
much branched; branches alternate, patent, several times divided. All 
parts of the frond are, at first, pellucidly articulate; in the older fronds 
the main stem and lower branches are coated with short curled fibres, and 
become not only opaque but nearly 1 mm. in diameter. Every articulation 
of the frond emits two or four opposite pinnae, not more than 1 mm. long, 
spreading horizontally, at nearly right angles with the branches, and 
hooked back at the point. Apices of the pinnules acute. Colour crimson- 
red. Substance not very soft. Adheres imperfectly to paper. 
South Australia (Eastern Bays), Victoria (Port Fairy). 
Antithamnion nigrescens J. Agardh. 
Frond erect, 6 cm. to 10 cm. high. Somewhat widely branched, densely 
pinnulated, opposite, distichous, pectinate ; the pinnae at the base are 
pectinate-pinnulate, pinnellae at the joints are short and incurved, 
sparsely branched, except below, simple, articulate. Colour dark-red, almost 
black when dry. 
Victoria (Port Phillip). 
Antithamnion dispar (Harv.) J. Agardh. 
= Callithamnion dispar Harvey. 
Frond pellucidly articulate, capillary, more or less pinnate, distichous; 
primary branches few, unequal, virgate, bipinnate ; pinnae opposite, spread- 
ing, unequal, one 'shortened, the other long and pinnulated ; pinnules 
opposite, equal, horizontal, thick, multifid, mucronate. Tetrasporangia 
sessile on the sides or ends of the pinnules. 
Attachment a small disc. Fronds solitary or few together, 2 cm. to 8 cm. 
high, irregularly branched, distichous, pellucidly articulate throughout. 
Branches opposite, alternate, lateral, very unequal in length, long and short 
intermixed, simple, virgate, erecto-patent ; when not opposite each is 
opposed by a small ramulus. Both primary and secondary branches are 
furnished at every joint with minute, multifid, dichotomous whorled ramuli, 
