All parts of the frond are, at first, pellucidly articulate, the articulations uni- 

 formly short, rarely twice or thri(;e as long as broad, and generally not more 

 than 1 ^ as long ; in the older fronds the main stem and the lower part of the 

 principal branches are coated externally with short curled fibres, and become 

 not only opaque but nearly i line in diameter. Every articulation of the 

 frond emits 2 or 4, opposite or quadrifarious pinnae, not more than | line 

 long, spreading horizontally, at nearly right angles with the branches, and 

 hooked back at the point. These pinna} are variously compounded in uni- 

 lateral, secund order ; the simplest bear a few erect secund pinnules along 

 their upper fiice ; more compound bear a second series along their upper 

 side ; and the most compound bear a third series (see fig. 3, 2, 4). Apices 

 of the pinnules acute. Fruit not observed. Colour a full crimson-red, 

 rather darker in drying. Substance not very soft. The young frond ad- 

 heres pretty closely, the older imperfectly to paper. 



Young specimens of the present beautiful species bear a very 

 near resemblance in habit and character to the C. plumula of 

 Europe, and which is found, though very rarely, in Tasmania. 

 They are chiefly to be known by their greater rigidity and 

 the general shortness of the articulations. Old and full-grown 

 plants are much more easily distinguished, for in them the 

 main filaments and some of the larger branches become clothed 

 with a gradually increasing stratum of woolly hairs, which finally 

 completely cover the joints, and greatly increase the apparent 

 diameter of the filament. The greate rrigidity of frond causes 

 the branches and ramuli constantly to stand apart, so that the 

 plant has a somewhat fan-like outline. Fruit, of both kinds, is 

 still a desideratum. 



Fig. 1. Callithamnion simile, — tlie twtural size. Fig. 2, 3, 4, different 

 articulations of the stem, with variously compound ramuli. 5. One of the 

 ultimate pinuulsc : — magnified. 



