CBRJJOA4 153 



gracillimum, it will be peroeived thai Bcopic cha- 



racters have a greater resemblance to those of ( '. Born ri s 

 from which the axillary ramulus and the distichous growth 

 chiefly separate it. Only a very few specimens have been 

 found, and these accompanied ('. thuyoideum, growing on 

 the perpendicular Bides of Bteep rocks at the extreme Emit 

 of low water. 



litl'J. ^racillimum {The very graceful Callithamnion) ; frond 

 distichously branched, Em-shaped; stems capillary, decom- 

 posito-pinnate j upper plumules Long, narrow, ovate or 

 lanceolate, spreading, bi-tripinnate ; joints of the stem cylin- 

 drical, three or torn- times, of the pinnae two or three I 

 Longer than broad, reinless ; tetraspores borne on the tips of 

 the pinnules, Ag. Sp. Alg.v. 2. p. 168. (Atlas, PL LIX. 

 Fig. 274.) 

 Jlah. Atlantic- coasl of France, Qratelowp. South and i 



England. On mud-covered perpendicular rocks, near Low- 

 watermark. Annual. Summer. 

 This extremely elegant plant, perhaps the most graceful 

 of the very beautiful genus to which it belongs, was 

 gathered on the shores of France by M. Grateloup. From 

 Mrs. Griffiths (who discovered magnificent specimens 

 growing along the mud-covered base of the harbour-pier at 

 Torquay, in which Locality it may be found in mere or Less 

 plenty every summer) it received the very appropriate 

 name of " Fern-leaf" aptly expressing the finely pinnated 

 character of the branches, which do indeed closely resemble 

 fairy ferns. As a species, it is very closely related I ( 

 thuyoideum, with which it agrees in many characters, but 

 from which it may be known by the greater proportionate 



Length ami breadth of the plumules, their more distichous 

 arrangement and closer position, the shorter and more 

 cylindrical joints of the main branches, and Larger size of 

 the frond. Both species agree in producing their tebra- 

 spores on the tips of the ultimate ramuli, a character by 

 which they diner from all other British species with 

 decompound-pinnate fronds. 



rhuyoideum ( 7' I \lUthammon) \ Btem capillary, 



undivided, sel with alternate, distichous, repeatedh pinnate 



branches, with a narrow lanceolate outline: branches fur- 

 nished with bipinnate or tripinnate plumules; articulations 

 of the branches 2-6 time-, of the pinnules about twi 



long as broad j tetraspores borne on the tip? of the nil: 



