38 Minnesota Algae 



expansion takes place chiefly near the periphery, so that the frond be- 

 comes a hollow body. The walls of the sac then give way, and, as the 

 expansion proceeds, orifices are formed in different parts, until the whole 

 becomes a coarsely latticed sac or clumsy net of irregularly lobed form. 

 Then this becomes broken up into irregular fragments of all shapes and 

 sizes each of which recommences the expanding growth, and becomes a 

 latticed frond." — Henfrey. 



go. Clathrocystis robusta Clark. The Holophytic Plankton of Lakes Atit- 

 lan and Amatitlan, Guatemala. Proc. Biol. Wash. 21: 94. 1908. 



Colony when young dense, spherical, surrounded by a gelatinous tegu- 

 ment, later perforate, clathrate or broken up into elongate rounded lobes; 

 tegument tardily deliquescent, finally wholly dissolving, leaving a densely 

 cohering mass of cells; cells 6-9 mic. in diameter, spherical or oval; cell con- 

 tents (in formalin) bright blue-green. 



Central America. Forming a flocculent bright blue-green scum on sur- 

 face of water. Lake Amatitlan, Guatemala. February 1906. (Meek). 



Genus GOMPHOSPHAERIA Kuetz. 

 Alg. Exsicc. Dec. 16. no. 151. 1836. 



Colonies spherical or ellipsoid, mucous, solid, free-swimming; tegument 

 colorless or yellowish, usually thick, soon diffluent; cells pear-shaped or 

 heart-shaped, rarely somewhat spherical, grouped in pairs, few in num- 

 bers, disposed chiefly towards the periphery of the tegument; cell con- 

 tents often granular, bluish or greenish; reproduction by cell division 

 alternately in three directions, 



I Cells 4-5 mic. in diameter, 8-12 mic. in length C. aponina 



II Cells 3.2-4 mic. in diameter, spherical; cell contents pinkish or brown- 



ish G. rosea 



51. Gomphosphaeria aponina Kuetzing. Alg. Exsicc. Dec. 16. no. 151. 1836. 

 De Toni. Syll. Algar. 5: 97- 1907. 

 WoUe. Fresh-Water Algae United States. 328. pi. 210. f. 20-22. 1887. 

 Bennett. Plants of Rhode Island. 115. 1888. WoUe and Martin- 



dale. Algae. Britton's Catalogue of Plants found in New Jersey. 

 Geol. Surv. N. J. 2: 611. 1889. Tilden. List of Fresh-Water Algae col- 

 lected in Minnesota during 1893. Minn. Bot. Studies, i: 31. 1894; List of 

 Fresh-Water Algae collected in Minnesota during 1895. Minn. Bot. Studies. 

 600. 1896; American Algae Cent. III. no. 300. 1898. Lemmermann. 



Planktonalgen Ergebn. einer Reise. n. d. Pacific. Abh. Nat. Bremen. 16: 

 313. 1899. Setchell. Notes on Cyanophyceae. — III. Erythea. 7: S4- 1899. 

 Bessey, Pound and Clements. Additions to the Reported Flora of the 

 State. Bot. Surv. Nebraska. 5: 12. 1901. Snow. The Plankton Algae of 

 Lake Erie. U. S. Fish Commission Bull, for 1902. 22: 392. 1903. Setchell 

 and Gardner. Algae of Northwestern America. Univ. Calif. Pub. Bot. i: 

 180. 1903. Lemmermann. Algenfl. Sandwich-Inseln. Bot. Jahrb, 34: 616. 

 1905. Riddle. Brush Lake Algae. Ohio Nat. 5: 268. 1905. Clark. 

 The Holophytic Plankton of Lakes Atitlan and Amatitlan, Guatemala. 



