2, Trichogyne clavate 4 



2. Trichogyne spatula-shaped, eUipsoid, or ovate 3 



3. Trichogyne spatula-shaped — — B. vagum 



3. Trichogyne ellipsoid or ovate B. Boryanum 



4. Carpospores developed in outer part of a branch-whorl B. ectocarpum 



4. Carpospores developed in inner part of branch-whorls in axils of 



branches near the main axis B. moniliforme 



Batrachospermum Boryanum Sirodot 1884, p. 246 

 PI. 136, Fig. 5 



Thallus densely branched and embedded in copious mucilage, 

 gray-green to golden-green in color; whorls conglomerate, usually 

 closely arranged to form a decided beaded appearance; secondary 

 branches either few or many; corticating branches many, loosely 

 arranged; apical hairs few, shghtly swollen at the base; dioecious; 

 carpogonia on a primary lateral branch or rarely on the branches 

 from the corticating filaments, the trichogyne ellipsoid or oval; carpo- 

 spore masses numerous, scattered throughout the branch- whorls. 



Walnut Lake, Michigan. 



Batrachospermum Dillenii Bory 1823, p. 226 

 PI. 135, Figs. 4-6 



Thallus irregularly and sparingly branched, the branches rather 

 rigid, straight or slightly curved; plant 2-5 cm. long; cortical fila- 

 ments highly developed and inclosing the axial filament with a 

 parenchymatous layer; lateral branching system poorly developed, 

 the branches short with few repeated branchings, forming nodal 

 clusters a considerable distance apart so that a jointed appearance 

 is produced macroscopically; in the apical region the abbreviated 

 out-turned branches numerous, compactly clustered, composed of 

 subglobose or ovoid cells and ending in long cylindrical cells but 

 without terminal setae; plants dioecious, the carpogonia on very 

 short branches, produced directly from the main axis, not in whorls 

 of branches, triangular in shape, narrowed above and then slightly 

 inflated to form a claviform or oblong trichogyne; antheridial cells 

 formed in transverse zones from short, out-turned branches, many 

 occurring in ohe cluster. 



Scrapings from a log in flowing water. Wis. 



Batrachospermum ectocarpum Sirodot 1884, p. 222 



PI. 136, Fig. 4 



Thallus much-branched, the whorls of branches well-developed, 



lobed and broadly rounded, close together, the internodes short; 



inclosed in copious rather firm mucilage, gray- or olive-green, up 



[567] 



