A minute species, one of the least developed of the genuine 

 members of the genus, and more remarkable for its rarity than 

 its beauty. It was originally discovered in the neighbourhood 

 of Bantry, by the late Miss Hutchins, and first described and 

 figured in the appendix to Dillwyn's Conferva. About the same 

 time specimens slightly differing in character, were gathered in 

 Orkney by Messrs. Hooker and Borrer, and received the name 

 of ohvacea : and thus two species have generally been recognised. 

 A careful comparison of the characters attributed to each, with 

 an examination of specimens from several localities, has satisfied 

 me that the differences do not warrant the retention of two 

 species, and I consequently here unite the S. olivacea of authors, 

 to the older & radicans. The form to which the name olivacea 

 was given, is rather more erect, and less disposed to throw out 

 radicles than common ; but there are no other characters by 

 which it can be distinguished. I speak of the S. olivacea of 

 British authors ; the plant so called by Lyngbye appears to be 

 somewhat different, and is either a distinct species or a state of 

 S. cirrhosa. 



Fig. 1. Tufts of Spiiacelaria radicans : — of the natural size. 2. Filaments 

 — magnified. 3. Apex of a fertile brauch : — more highly magnified. 



