84 CONFERVACE^. 



To this species I am disposed to refer a specimen which was provisionally named 

 C. jyrasina, formerly received from Professor Bailey, who found it abundantly in the 

 Hudson at West Point, where it is thrown ashore after storms. I have also received a 

 fresh-water specimen collected by Dr. Bigelow when engaged on Lieutenant Whipple's 

 expedition to the Pacific. 



20. Cladophora glomerata, Linn. ; filaments tufted, bushy, somewhat rigid, much 

 branched, bright grass-green ; branches crowded, irregular, erecto-patent, repeatedly 

 divided ; ultimate ramuli secund, subfesciculate ; articulations 4-8 times as long as 

 broad. Bilhc. Conf. t. n. E. Bot. t. 2192. Harv. Man. Ed. 1, p. 134. 



Hab. In streams, lakes, and rivers. Probably common. 



I have received North American specimens fi-om Milton, Saratoga County, N.Y., and 

 from Lake Erie ; also from the Mexican Boundary Surveying Expedition. 



IV. CEMTOM.OB.TRA, Kiitz. (May, 1845.) 



Filaments (not gelatinous), membranaceous or cartilaginous, unbranched, attached, 

 or floating, articulated ; formed of a string of oblong cells, the basal cell longer than 

 the rest. Articulations filled with granular endochrome. (Marine.) 



The genus, as here adopted from Kiitzing, is intended to include most of the marine 

 species of the older Conferva, which have unbranched filaments and articulations usually 

 longer than their diameter. It differs from Cladophora solely in being branchless. 

 From Hormotrichum it is less easy to point out a clear distinctive character, unless we 

 seek it in the substance of the cell-coats, and in the shortness of the cells usual in that 

 genus. The name Aplonema was proposed for this group by Mr. Hassall (Brit. Ft. 

 W. Conf. p. 213.) only two months subsequently to the publication of Kiitzing's genus, 

 which tiius establishes its priority on very narrow evidence. It forms a part of the 

 Agardhian Lychcete, published in 1846 ; a group that includes both simple and branched 

 species, and which is thus characterised by its author : — 



Lychjite, J. Ag. ; " fronde sub-heterogenea, articulo infimo (in simplicibus),aut infimis 

 raraorum (in ramosis) dissimilibus et non mutandis, superioribus omnibus continua 

 subdivisione iterum iterumque divisis atque coniocystis externis distinguendum." 

 Alg. Ined. Ed. 2, No. 9- (Lycluete mirahilis). 



I prefer, with Kiitzing, to keep the branching and unbranched species in separate 

 genera, as being a more obvious, if not more natural arrangement. However, the 

 whole subject of tlie natural arrangement of these obscure plants is open to future 

 discussion. The present is but a temporary settlement of the question. 



