BATRACHOSPERMUM. 57 



Besides this typical form Plate LXIII, figs. 6 and 10, there 

 are many varieties, varying in color, in size and other par- 

 ticulars. The following may be noted as varieties. 



Var. PULCHERRIMUM, Bory. 



Violet or purple, internodes almost naked, branches 

 elongated, whorls rather distant globose. Plant 3-5 inches 

 long. 



Var. SETIGERUM, Eab. 



The extremities of the moniliform branchlets drawn out 

 into a long -setiform thread. 



Var. CONFUSUM, Hass. 



Internodes short, robust and corticulate, whorls approxi- 

 mate with numerous interstitial ramuli irregularly disposed. 



Var. KUEHNIANUM, Eab. 



Eather a small form, blue-green, or purplish-green, stern 

 simple, almost naked, whorls distant and slender. 

 Plate LXIV, figs. 4, 5. 



Mountain springs, Pennsylvania. 



Var. ATRUM, Harv. 



Internodes long, somewhat corticulate, whorls imperfectly 

 developed, interstitial ramuli very short, often only t;\ r o- 

 celled, color very dark or black. 



Syn. Conferva atm, Dillw. Batrachospermum detersum, Eiig. 

 Bot. Lemanea setacea, Bory. 



Rivulet, Catalina Mt., Arizona. 



Plate LXIV, fig. 6, natural size. Plate LXIII, fig. 9, 

 specimens magnified. 



4 



BATRACHOSPERMUM VAGUM, Ag. 



Very variable, but a large and well -developed species, two 

 to ten inches long, almost invariably bluish-green ; distin- 

 guished from the preceding, besides the color by the density 

 of the interstitial ramuli, , and the rather imperfectly de- 

 veloped whorls of the main stems ; the ramuli are often so 

 impacted that the whorls are not apparent except towards 

 the ends of the stems and on the younger branches. 



Syn. Batmcliosperma turfosa, Bory. 



Plate LXV, figs. 1, 2, older fronds; figs. 3-6, younger 

 branches. Only typical specimens from Maine and Canada, 



