co>;fervace.e. 67 



coating of the frond, tlie inner of three or four rows of large, colourless, oblong, irregu- 

 larly anastomosing cells. The tube is traversed and crossed by a few slender, cylindri- 

 cal, long jointed filaments issuing from the inner periplieric cells. Globose masses of 

 fructification are attached to the inner face of the tubular frond, either at the nodes or 

 l)etween them, without any apparent order. They consist (as in Batrachospermum) 

 of very densely crowded, moniliform, subsimple strings of cellules radiating from a 

 central point. The general colour is olivaceous when recent, and very opake ; it becomes 

 a livid purplish in drying. Substance firmly cartilaginous or subcoriaceous. It does 

 not adhere to paper in drying. 



Agardh describes a L. variegata, " filis moniliformibus variegatis," as sent to him by 

 Muhlenberg, from North America. By the description given it seems merely to differ 

 from the common L. torulosa in being variegated with alternate bands of dark and 

 pale, a character most probably dependant on the state of the specimens. I am indebted 

 to Dr. Short of Kentucky, for fine specimens of the ordinary form. L. fluviatilis, which 

 is the commonest European species, has not been sent to me from America. 



Order VI. CONFERVACEiE. 



Confervew^ J. Ag. Alg. Medit. p. 1 2. Harv. Man. Ed. 1 and Ed. 2, p. 196. Lindl. 

 Veg. Kingd.p. 18. Confervoidea', Endl. BdSupp.p. 14. Confervacece, Berk. Crypt. 

 Bot. p. 131. Confervacew and Chcetopihoroidece., {partly) Dne. class, p. 31, Kutz. Sp. 

 Alg. pp. 363-531. 



Diagnosis. Green, marine or fresh water Algee, composed of articulated threads or 

 filaments, and of cylindrical cells usually longer than their diameter. Endochrome dif- 

 fused, or filling the cavity of the cell. Zoosjwres minute, indefinitely numerous in each 

 cell. 



Natural Character. Boot rarely more than a mere point of attachment, and often 

 perishing on the evolution of the frond, which then floats on the surface of the water. 

 Frond in all cases filamentous, composed of strings of truncated, more or less cylindri- 

 cal cells, placed end to end, and usually longer than their diameter. These cells are 

 never branched, like those of the Sip>honacece, and are usually much shorter in propor- 

 tion to their diameter than in that order ; but as compared with those of most of the 

 filamentous Algas they are long, varying however extremely in different species. The 

 endochrome generally fills the cavity or primordial utricle of the cell, but varies greatly 

 in density. In some cases it is thin and watery, and in others very dense, granular, 

 and subopaque. It is sometimes arranged in transverse bands. In most cases the 

 cell wall is membranaceous, soft, but of firm texture ; but in Draparnaldia and 

 Chcetophora., the filaments are invested with gelatine, and in the latter genus numerous 



