stem, taper at each end, and are closely pinnated with a second or third 

 series, and all the branches, of every series, are bordered with setaceous, 

 horizontally patent, minute ramuli. These last are generally strictly mar- 

 ginal, but sometimes spring from the disc. The conceptacles are about the 

 size of poppy-seed, globose, inflated, with a dark-red centre, and are com- 

 monly sessile on the margin of the frond ; their walls are thick, formed of 

 two strata of cells, similar to those of the intermediate and cortical layers 

 of the frond ; the placenta is at the base of the nearly-spherical loculus, 

 and bears a tuft of spore-threads. The spores are of large size (for the 

 family), and oblong, and formed in all the cells of the spore-thread. The 

 tetraspores are thinly scattered among the cortical cells of the larger 

 branches. The colour is a brilliant rosy-crimson. The substance softly 

 membranaceous and very flaccid, and the plant closely adheres to paper in 

 drying. 



This has so much the ramification of Turner's Fucus divaricatus 

 (Turn. Hist. t. 181), that I should unhesitatingly have referred 

 it to that species (specimens of which I have never seen), had not 

 Professor J. Agardh, from an examination of authentic mate- 

 rials, pronounced that plant to be a Chylocladia, to which genus 

 he could not possibly refer the flat-fronded species here figured. 

 On a closer examination, I venture to associate our plant gene- 

 rically with Fucus Usnea, R. Br., which Agardh makes the type 

 of his genus Hymenocladia. The ramification and structure of 

 the frond are similar, nor is there any great difference in fructi- 

 fication. Dr. Sonder, on the contrary, regards our H. divaricata 

 as being scarcely distinguishable from Hypnea seticulosa, an 

 opinion in which I cannot coincide, as that plant has a cylindri- 

 cal frond of different structure, and the fructification is equally 

 diverse. 



Hymenodadia Bamalina, Harv., from King George's Sound, 

 is possibly only a less branched variety of the present, but if so, 

 is at least a remarkable form. 



Fig. 1. Hymenocladia divaricata, — the natural size. 2. Small portion of 

 the frond, bearing conceptacles. 3. A vertical section through a con- 

 ceptacle. 4. Spore-strings from the same. 5. Cross section of a branch, 

 showing its structure, and the position of the tetraspores in the cortical 

 layer. 6. Tetraspores : — the latter figures variously magnified. 



