CLOSTERIUM. 45 



■C. cosTATTJM, Corda. Plate VII, fig. 19. 



Fusiform, more or less curved, 6-8 diameters in length, 

 ends rounded ; tapering from the middle to about one-third 

 the largest diameter ; vacuole large, containing many danc- 

 ing granules. Membrane in front view has 5, or rarely 6-8 

 longitudinal striae or costae. Zygospores spherical or ovate. 

 Diameter 63-70 yw. 



Frequent in marsh pools and the like localities. 



€. Delpontii, Klebs. {G. Orassum, Delp.) Plate VI, fig. 9. 



Cells cylindrical, somewhat inflated in the middle, gradu- 

 ally tapering to an obtusely rounded apex ; distinctly striate 

 with one, two or three sutures about the middle ; cell twenty 

 times (more or less) longer than broad. 



Diameter 35-45 yw. 



Delponte's name of Crassuni having been previously ap- 

 plied to another species by Rabenhorst, Klebs changed it. 



C. LiNEATUM, Ehrb. Plate VII, fig. 16. 



Long, straight and cylindrical in the center, ends greatly 

 attenuated and slightly incurved, apices obtusely rounded, 

 distinctly striate ; chlorophyl globules, about twenty in each 

 semi-cell, placed in a single axillary series ; vacuoles small, 

 remote from the apices. 

 Diameter 24-36 /^. 



Pennsylvania, New Jersey, and probably every State. 



Var. cosTATUM. Plate 10, fig. 3. 



This variety differs from the usual form in having the 

 striae very thick and few in number. The figure represents 

 one of many fruiting specimens found by W. N. Hastings, 

 Eochester, N. H. Xl n 



C. Beaunii, Heinsch. Plate LfV-, fig. 19. 



Frond large, nearly straight, linear in front view, tapering 

 rather suddenly near the obtusely rounded apices, a central 

 suture ; 5 to 10 distinct longitudinal costae. Cells usually 

 brownish yellow about 12 times as long as wide. 

 Pictou, Nova Scotia. 



C. DECORUM, Breb. Plate VIII, fig. 1. 



Moderately arched, 12-16 diameters in length, gradually 

 tapering from the center to one-fourth or one-fifth of largest 

 diameter ; ends rounded ; vacuole small. Cytioderm finely 

 striate. Zygospores angular in European specimens. 



Diameter 34-41 /<. 



