\ 

 DRAPARNALDtA. 109 



c. acuta, Ag. Stems thicker, often 70 yw in diameter, arti- 

 cles 2-10 times longer. 



d. gracillima, Ag. Secondary branchlets rare. 



e. maxima. Wood. Stems attain diameter of 100 //, articles 

 much swollen, twice as long as wide. 



Plate XCII, fig. 1, a main stem with branches ; figs. 2, 3, 

 part of a rhizome, and smaller stem with branches ; 4, 5, 6, 

 young, not fully developed stems ; 7, 8, stems of branches 

 producing zoospores ; 9, ciliated zoospores ; 10, 11, 12, pro- 

 gressive stages of development and growth of zoospores. 



DRAPARNALDIA PLUMOSA, Ag. 



Cells of the main stems very slightly or not at all swollen 5 

 the fasciculate branches somewhat lanceolate in outline, not 

 so obtuse or oval as D. glomerata; beside these two rather 

 unsatisfactory differences the two species can not be sep- 

 arated. 



Found in similar localities. 



Diameter of cells of main stems about 45 // ; \-\\ times as 



long. 

 Diameter of cells of lower branches, 10-11 f^ ; 1-2 times 



as long. 



Syn. D. hypnosa, Bory. ; Batrachospermum plumosum, Vauch. ; 

 D. pulchetta, Kg. 



Plate XCIV, figs. 1, 2, specimens of a rather robust form. 



DRAPARNALDIA SPINOSA, Kg. 



Articulations of stems average li diameters, ranging from 

 I to 1, rarely 2 diameters ; sparsely branched ; branches 

 opposite, at right angles ; fascicles somewhat triangular in 

 outline ; stems of branches short, thick at the base, rapidly 

 tapering to an acute point or seta. 



A distinct form, hitherto found only in one locality in the 

 United States, in a streamlet issuing from a large, high 

 mountain spring, Carbon County, Pennsylvania. 



Diameter of cells of main stems, 45-75 ,/u; f-2 times as 



long. 

 Diameter of cells of branches, 20-25 p. 



Rabenhorst suggests the species of Kuetzing under this 

 name approximating the European D. graeiUima, Ag. Our 

 form appears more distinct. 



Plate XCIII, figs. 1-4, larger and smaller stems ; figs. 5-8, 

 branchlets of various sizes. 



