THE GREEN ALGAE OF NORTH AMERICA 81 



3oa. Articulations long, up to 20 diatn. 3. C. Rudolphiana. 



3oa. Articulations not over 8 diam. long. 31. 



For No. 45. 



45. Forming a dense hemispherical tuft, with or without slender loose 

 tufts arising from it. 60. (7. hemisphaerica. 



45. No dense hemispherical tuft. 458. 



45a. Substance soft and silky; cells 4-12 diam. long; ramuli erect. 



45b. 

 45a. Substance crisp or harsh; cells 1-5 diam. long; ramuli patent. 



45C- 



45b. Branching continuously dichotomous, except as to ultimate ramuli. 



9. C. Stimpsoni. 

 45b. Main branching dichotomous ; lesser branches and ramuli dense, 



largely secund. 19. C. crystallina. 



45c. Crisp but not. harsh ; cells 3-5 diam. long ; ramuli scattered and 



distant. 56. C. piscinae. 



45C. Stiff and harsh ; cells mostly 1-2 diam. long ; ramuli closer, often 

 in secund series. 57. C. rigidula. 



Page 335, in Key to the Fresh Water species, for Nos. 5 and 

 6, substitute, 



5. Main filaments long, with few branches. 5a. 



5. Filaments freely branching. 6. 

 5a. Strongly moniliform ; cells averaging little over i diam. long. 



62. C. moniliformis. 

 5a. Cells slightly swollen, 4-6 diam. long. 51. C. insignis. 



6. Ramuli mostly unicellular. 48. C. oligoclona. 

 6. Ramuli pluricellular, long-celled. 6a. 



6a. Branching irregular ; branch-bearing cells appearing forked at sum- 

 mit ; growing at bottom of cold, deep lakes. 61. C. profunda. 



6a. Branching alternate, usually dense ; branch-bearing cells normal ; 

 plant of shallow water. 49. C. crispala. 



Page 337, after first paragraph, add, 



C. RUDOLPHIANA forma eramosa N. L/. Gardner forma 

 nova. Ramis praelongis, subsimplicibus. 



Branches very long, subsimple. In warm salt water pool, 

 Key Route Power House, Oakland, Cal., April, 1915. Type 

 in herb. N. L. Gardner, No. 2856. 



Apparently a result of the abnormal, uniformly high tem- 

 perature. 



Page 349, after C. TRICHOTOMA, add, 



Var. ELONGATA Collins in P. B.-A., No. 2141. Growing in 

 deeper water, up to 3 dm. long, little branched below, freely 



