196 Minnesota Algae 



New Jersey. Geol. Surv. N. J. 2: ^7. 1889. 



Plate IX. -fig. 22. 



Plant mass gelatinous, somewhat membranaceous, deep blue-green; 

 filaments 7-8 mic. in diameter; sheaths delicate; trichomes moniliform, 

 .slightly curved or nearly straight, more or less parallel; cells about half as 

 long as wide, sometimes separated; heterocysts compressed globose, homo- 

 geneous, brownish yellow; cell contents granular, light blue-green. 



New Jersey. On the trunks of trees, low down near the water's edge 

 in swamps. (Wolle). 



361. Anabaena gelatinosa Wood. Contr. Hist. Fresh-Water Algae North 



America. 38. pi. 2. f. 4. 1872. De Toni. Syll. Algar. 5: 461. 1907.- 

 Plant mass gelatinous, mucous, indefinitely expanded, somewhat pellu- 

 cid, with a brownish tinge; sheaths not present; trichomes somewhat 

 curved, rather distant, not entangled; cells globose; heterocysts about equal 

 to the cells in diameter, spherical or rarely oblong; cell contents homo- 

 geneous, light golden yellow or light blue-green; gonidia spherical, termi- 

 nal. 



Pennsylvania. Near Philadelphia. (.Wood). 



362. Anabaena subrigida (Wood) De Toni. Syll. Algar. 5: 461. 1907. Wood. 



Contr. Hist. Fresh- Water Algae North America. 42. pi. 3. f. 2. 1872. 



(Dolichosperm um subrigidum Wood). 



Plant mass floating; trichomes single, straight or nearly so, very small; 



cells cylindrical or somewhat spherical, distinct; heterocysts cylindrical, 



short, single, distinct; gonidia single or in pairs, slightly constricted in the 



center, not contiguous to heterocysts; cell contents light green. 



Pennsylvania. In scum floating on ditches. Near Philadelphia. (Wood). 



' ' Genus APHANIZOMENON Morren. 



Hist. Genre Nouv. Conf. 11: 11. 1838. 



Colonies thin, feathery, plate-like or spindle-shaped bundles, blue- 

 green, floating; sheaths not present; trichomes short, tapering at the ends, 

 agglutinated; heterocysts scattered; gonidia cylindrical, much elongated, 

 solitary, developed sparingly between the heterocysts. 



363. Aphanizomenon flos-aquae (Linn.) Ralfs. On the Nostochineae. Ann. 



Mag. of Nat Hist. 5: 340. pi. 9. f. 6. 1850. Bornet and Flahault. 

 Revis. des Nostoc. Ann. Sci. Nat. Bot. VII. 7: 241. 1888. De Toni. 

 Syll. Algar. $: 468. 1907. 



Arthur. Some Algae of Minnesota Supposed to be Poisonous. Bull. 

 Minn. Acad. Nat. Sci. 2: (App.) i. 1883. Wolle. Fresh- Water Algae U. 

 S. 291. pi. 198. f. 7, 8. 1887. Tilden. American Algae. Cent. II. no. 173. 

 1896; List of Fresh-Water Algae collected in Minnesota during 1895. Minn. 

 Bot. Studies, i: 599. 1896. Riddle. Algae from Sandusky Bay. Ohio Nat. 

 3: 317. 1902. Snow. The Plankton Algae of Lake Erie. U. S. Fish Comm. 

 Bull, for 1902. 22: 392. 1903. Collins, Holden and Setchell. Phyc. Bor.-Am. 



