2o8 Minnesota Algae 



.becoming lamellose, yellowish brown and up to 3 mic. in thickness; trich- 

 omes 11-22 mic. in diameter, constricted at the joints; apical cell rotund; 

 cells 3-9 mic. in length; transverse walls sometimes granulated; cell con- 

 tents often filled with coarse granules, blue-green. 



Rhode Island. Quidnessett. (Bennett). New Jersey. Frequent on 



stones in ponds or floating. Hammonton. (Wolle). Pennsylvania. Form- 

 ing little dark green mats, growing attached to mosses in large spring that 

 supplies Belief onte with water. (Wood). In spring. Bethlehem. (Wolle). 

 Maryland. Falls of Deep Creek. (Smith). Ohio. Plankton. Lake Erie. 

 Put-in-Bay. (Snow). Minnesota. Minneapolis. (Wolle). 



383. Plectonema woUei Farlow. Remarks on some Algae found in the 

 Water Supplies of the City of Boston. Bull. Bussey Inst. yT. 1875. 

 Gomont. Monogr. Oscill. pi. i. f. i. 118. 1893. De Toni. Syll. Algar. 

 S: 489. 1907. 



Rabenhorst. Die Algen Europas. no. 2440. 1876. (Lyngbya wollei 

 Farlow). Farlow, Anderson and Eaton. Algae Am. Bor. Exsicc. no. 46. 

 3877-1889. Wittrock and Nordstedt. Algae Aq. Dulc. Exsicc. no. 279. 

 1879. Farlow. On some Impurities of Drinking-Water caused by Vege- 

 table Growths. Supp. First Ann. Rep. Mass. State Bd. Health. 131. 1880. 

 Wolle. Fresh- Water Algae U. S. 297. pi. 200. f. 6-8. 1887. Collins. Algae 

 of Middlesex County. 14. 1888. Bennett. Plants of Rhode Island. 114. 

 1888. Wolle and Martindale. Algae. Britton's Catalogue of Plants found 

 in New Jersey. Geol. Surv. N. J. 2: 608. 1889. Collins, Holden and Setch- 

 ell. Phyc. Bor. -Am. Fasc. 2. no. 55. 1895. Tilden. American Algae. Cent. 

 II. no. 177. 1896; List of Fresh-Water Algae collected in Minnesota dur- 

 ing 1895. Minn. Bot. Studies, i : 599. 1896. Collins. The Algae of Jamaica. 

 Proc. Am. Acad. Arts Sci. 37: 240. 1901. Snow. The Plankton Algae of 

 Lake Erie. U. S. Fish Comm. Bull, for 1902. 22: 392. 1903. Collins. Phyco- 

 logical Notes of the late Isaac Holden. — II. Rhodora. 7: 236. 1905. 



Plate XI, fig. 4, s. 



Plant mass caespitose, floating, blackish, rarely yellowish green; fila- 

 ments woolly, entangled, fragile (in dried specimens), somewhat straight 

 or variously curved, slightly branched; false branches solitary, rarely in 

 pairs, issuing in an oblique manner; sheaths colorless, sometimes yellowish 

 orange, lamellose with age, roughened in outline, up to 10 mic. in thickness; 

 trichomes 28-47 mic. in diameter, not constricted at joints; apical cell 

 rotund; cells 4-9 mic. in length; transverse walls not granulated; cell con- 

 tents finely granular, blackish or blue-green. 



Massachusetts. Attached to stones in rivers. (Wolle). Washed ashore in 

 large quantities. Horn Pond, Woburn; August 1890; Lake Quannapowitt, 

 Wakefield. (Collins). Rhode Island. Providence. (Bennett). Con- 



necticut. Attached to stones in swift water. Housatonic River, below 

 Great Falls, near New Milford. October 1890. (Holden). New Jersey. 

 "The floating mass was fully ten yards long, 2-3 yards wide, a foot or more 

 in thickness, and so densely matted, it was impossible to break through 

 with a row-boat." In pond near Stanhope; Sussex; Lake Hopatcong, Swarts- 



