V. CERAMIACE.E. 243 



Hab. On Zostera at Newhaven, Connecticut, Mr. Hooper, (v. s. in Herb. 

 Hooper). 



Filaments forming a dense, deep-purple fringe, two or three lines in length, to 

 the leaves of Zostera., excessively branched in a manner between alternate and 

 dichotoraous, the lesser divisions very generally secund. Branches flexuous, flabel- 

 liform. 



The American specimens seen are faded. In other respects they agree with 

 an authentic specimen received from Prof J. Agardh ; but I must add that this 

 species appears to me to border too closely on the following, which is of earlier date. 



19. Callithamnion virgatulum., Harv. ; filaments minute (2 — 3 lines high), 

 flabellately much branched from the base ; branches alternately decompound, 

 fastigiate ; secondary ones few, erect, straight, rod-like, frequently secund ; ramuli 

 short, secund, often rising from every node ; articulations about three times as long 

 as broad ; tetraspores elliptical, pedicellate, scattered on the branches. Harv. in 

 Hook. Br. Fl. 2, j9. 349. Harv. Phyc. Brit. L 313. 



Hab. Parasitical on Dasya ekgans, at Hellgate, New York, Mr. Walters, (v. v.) 



Fronds forming a dense velvetty pile, nearly of the same colour as the byssoid 

 ramelli of the Dasya, and therefore likely to be overlooked. Filame)its alternately 

 or secundly decompound, all the angles acute and branches and their divisions 

 straight and erect. Ramuli bud-like, secund, along the branches. 



20. Callithamnion Daviesii, Ag. ; filaments minute (2 — 3 lines high), tufted, 

 much branched ; branches curved, scattered, patent ; ramuli elongate, fascicled or 

 crowded toward the axil of the secondary branches ; tetraspores pedicellate, on sub. 

 axillary ramuli. J. Ag. Sp. Alg. 2, p. 11. Harv. Phyc. Brit. t. 314. Kiitz. Sp. 

 Alg. p. 638. Conferva Daviesii, E. Bot. t. 2329. 



Hab. Parasitical on Ceramium ruhrum. Boston Bay, Miss E. Brewer, Dr. 

 Durkee. (v. v.) 



Filaments about a line in height, generally forming a fleecy down on the Cera- 

 mium, more or less branched ; sometimes sub-simple. Colour, a pinky-red. 



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