V. CERAMIACEJi:. 215 



a single, naked, coloured cell ; the node coated with a definite band of large 

 cellules. 



Hab. On perpendicular rocks, densely covered with Fuci, near low-water mark. 

 Camden, Penobscot Bay, Mr. J. Hooper. Newburyport, Capt. N. Pike. (v. s. in 

 Herb. T. CD.) 



This spreads over the surface of the rock in dense, root-like patches. The 

 filaments are an inch or two in height, possibly more in full-grown specimens, 

 irregularly dichotomous, and furnished with scattered, lateral rainuli, which are 

 either straight, or slightly curved at the point. The stems spring from a mat of 

 confervoid fibres ; near the base the cortical layer of the nodes is very narrow, 

 the internode being formed of a single, thick- walled cell, containing a dark purple 

 endochrome. The nodes in the upper part of the filament have a wider, but always 

 a strictly defined band of cortical cells, and the internodes throughout the filament 

 consist of a single large cell filled with endochrome. Most of the branches in Mr. 

 Hooper's specimens throw out from several of the nodes, below the tips, a number 

 of secund, hyaline, root-like filaments, one-fourth of the diameter of the part from 

 which they spring, one rising from the marginal cell of each node. Fruit at present 

 unknown. 



I have the more pleasure in naming this curious plant after its discoverer, Mr. 

 J. Hooper of Brooklyn, because I believe it to be distinctly marked by the struc- 

 ture of its articulations, as well as by its creeping habit. The bearded extremities 

 of the branches afford a very unusual character, but I fear to ground a diagnosis 

 on them, as they do not occur in a specimen fi'om Capt. Pike, which differs in no 

 other respect from those collected by Mr. Hooper. 



4. Ceramium diaphanum, Roth ; filaments setaceous, attenuated upwards, rather 

 flaccid, irregularly dichotomous ; the branches set with short, lateral, dichotomous 

 ramuli ; internodes colourless, those of the main stems three or four times as long 

 as broad, of the ramuli short ; nodes swollen, coated with a definite band of pur- 

 ple cellules ; favellte near the ends of the branches or of small ramuli ; tetraspores 

 numerous in each node. J. Ag. Sp. Aly. 2, p. 12.5. Harv. Phjc. Brit. t. 193. 

 Hormoceras diaphaniim^ Kiitz. Sp. Alg. p. G75. Conferva diaphana, E. Bot. t. 1742. 

 Dillw. Con.f. t. 38. 



Hab. Boston Bay, Dr. Durkce. Nahant, Mrs. Mudge. New Bedford, Dr. Boche. 

 Providence, Mr. Olney and Prof. Bailey. New York Bay, Messrs. Hooper, Walters, 

 Pike, Calverley, &c. Key West, Mr. Binney, Dr. Blodgett, W.H. H. (v. v.) 



Frond two to four inches hioh, variable in diameter, as thick as hog's bristle or 

 as horse hair below, gradually attenuated upwards and nearly capillary above, 

 irregularly dichotomous, with many lateral, dichotomous branchlets of various 

 lengths ; apices rarely fastigiate, but more so in some varieties than in others. 



