202 FRESH-WATER A L G^ OP THE UNITED STATES. 



The color of the spore is orange brown, and the thick coat is slightly tinged with 

 yellowish. The mature oosporangium is somewhat flattened at the sides, not so 

 elliptical as the young spore, which I have figured. 



Fig. 5 a, pi. 18, represents a fragment of a filament showing young sporangia! 

 cells magnified 260 diameters ; 5 6, represents a branch with a youngish spore in it, 

 magnified 460 diameters; fig. 5 c, was taken from a male plant. 



IS. duniosa, WOOD. 



B. articulis diametro 1^-2 plo longioribus ; oogoniis pleriimque in ramornm brevissimorum 

 apicibus positis sed interdum lateralibus, plerumque sctam tcrminalem gereutibus; oosporis 

 enormiter ovalibus aut ovatis, nonnihil indistincte longitudinaliter oblique subarcte. striatis ; 

 antlieridiis bicellularibus, stipite instructis, cellula basale medio tumida, supra soepe contracta. 



Syn. D. dumosa, WOOD, Prodromus, Proc. Amer. Philos. Soc., 1869, p. 142. 

 Hob. In aquario meo. 



Joints 1^-2 times longer than broad; oosporangia generally placed upon the ends of short 

 branches but sometimes lateral, mostly carrying a terminal seta; resting spores irregularly 

 oval or ovate, somewhat indistinctly obliquely longitudinally and rather closely striate ; an- 

 theridia bicellular, furnished with a little stipe, their basal cell tumid in the middle, frequently 

 contracted above. 



Remarks. This species appeared spontaneously during the latter part of the 

 winter upon some large fresh-water algae which I was cultivating. It branches 

 irregularly and sometimes somewhat profusely, so as to have quite a bushy habit. 

 The antheridia appear to produce a single spermatozoon in the terminal cell ; at 

 least as far as my observation has gone this is true. I think I have always found 

 the distal cells of fertile plants emptied of their contents, as though they had fur- 

 nished the androspores which had grown into the antheridia. This species is 

 closely allied to B. gracilis, of Pringsheim, from which it differs in the position of 

 the oogonia, in the relative breadth and length of the cell, and the number of cells 

 composing the antheridia. 



Fig. 6 a, pi. 18, represents a filament of this species magnified 260 diameters; 

 6 b, a male plant magnified 750 diameters. 



B. Canbyii, WOOD. 



B. permagna ad .035" longa, sparse ramosa; articulis sterilibus diametro-2-8 plo longioribus: 

 oogoniis lateralibus vel in ramulorum apicem positis, transverse enormiter ovalibus; oosporis, 

 transverse enormiter ovalibus, plerumque nonnihil triangularibus, oogonii lumen replentibus; 

 sporodennate crasso, baud costato, enormiter punctato ; antheridiis bicellnlaribiis. 



Diam. Cell, steril. 71J V ^V = .00066001. Spor. transv. T Jfo" = .00226. 



Syn. B. Canbyii, WOOD, Proc. Amer. Philos. Society, 1869, p. 142. 



Hab. In aquis quietis, prope Hibernia, Florida ; (William Canby). 



B. very large, attaining a length of more than one-third an inch, sparsely branched ; sterile 

 joints 2 to 8 times longer than broad ; oosporangia lateral or placed upon the ends of branches, 

 irregularly transversely oval ; oospores of a similar shape, often a little triangular, filling the 

 cavity of the sporangium ; spore coat thick, not costate bnt irregularly punctate. 



Remarks. It affords me great pleasure to dedicate this very handsome species 

 to Mr. William Canby, by whom it was collected in Florida, as an acknowledg- 

 ment of favors received, and as a testimony of respect and high regard for him 



