of this plant that the accurate Lyngbye may well be forgiven for 

 considering them to be distinct species. Few persons on inspec- 

 tion of our plate, would suppose that the bushy and broom-like 

 upper figure, was identical in species with the feathery plant re- 

 presented below ; even their microscopic characters are widely 

 dissimilar. Yet, observation, the true test of species, has traced 

 the one form into the other ; and I possess a suite of specimens 

 communicated by Miss Cutler and Mrs. Griffiths, which clearly 

 demonstrate the transition. 



Sphacelaria scoparia has been long known to botanists, having 

 been noticed by Bauhin, and figured by Dillenius in his admi- 

 rable work. It is very common on the several coasts of Europe, 

 both Atlantic and Mediterranean, and probably extends to other 

 tropical shores besides those of the Canary Islands. I have 

 gathered it in two localities at the Cape of Good Hope. Further 

 south, its place is taken by an analogous form (S. funicular is, 

 Mont.), which is found at the Auckland Island, and in New Zea- 

 land, in which Island some other remarkable SjjJiacelarice occur. 

 Of these the most curious is S. hordeacea, whose branches are 

 tipped with spikes of utricles, subtended by ramuli, and closely 

 resembling miniature ears of barley. Other species of the genus 

 inhabit every zone, from North Cape to Cape Horn ; but tropi- 

 cal algae have been, as yet, so imperfectly investigated, that it is 

 premature to assert to which zone the maximum of the genus 

 belongs. At present the evidence is in favour of the temperate 

 zones of the northern hemisphere. 



Professor Kiitzing has, in his ' Phycologia Generalis/ constituted 

 S. scoparia the type of a distinct genus, and S.filicina that of 

 another. The grounds of such separation are, in my opinion, very 

 insufficient to warrant the dismemberment of so natural and well 

 defined a group as the Spliacelarice of Lyngbye appear to be. 



Fig. 1. Sphacelaria scoparia; in summer: — natural size. 2. Branclilct of 

 the same : — magnified, 3. S, scoparia ; in winter: — natural size. 4. Branch- 

 let of the same. 5. Cross section of the stem, surrounded by accessory 

 fibres : — magnified. 



