152 



tion of the plant therefore remains less satisfactory than might be 

 the case were spores present. However, aside from the absence 

 of spores the agreement is close between the Chilson Lake plants 

 and German specimens (from the biological station at Plon), dis- 

 tributed as No. 587 of the Phykotheka universalis of Hauck and 

 Richter under the name Gloiotricliia echinulata. The most 

 striking difference noticed in comparing fluid-preserved materials 

 of the Chilson plant with the dried specimens issued under this 

 No. 587 and the figures accompanying this number is the greater 

 development of terminal hairs of the Chilson specimens. The 

 length of these nearly colorless hairs is commonly greater than 

 the whole diameter of the darker and denser central portion of 

 the sphere. But the delicate terminal portion of the hair does 

 not preserve well in drying and the difference is less striking, 

 though still apparent, when dried specimens of the two are com- 

 pared. However, the length of the hair varies with the age of 

 the colony and in certain stages the hairs may be entirely want- 

 ing. The colonies evidently multiply very rapidly through the 

 agency of hormogonia and before a filament breaks up into these 

 hormogonia, the terminal hair-like part falls off. 



The Gloiotricliia echinulata is accompanied by a relatively small 

 quantity of a spore-bearing Anabaena, another alga belonging also 

 to the blue-green class. The Anabaena forms still more minute 

 colonies, which are of a yellowish color. 



The "flowering" or "blossoming" of lakes, due to the alga 

 Gloiotricliia echinulata and exhibiting the phenomena observed by 

 Mrs. Smith, does not seem to have been recorded, so far as the 

 writer can discover, for the eastern portion of North America. 

 But it appears to be common in Minnesota and has been reported 

 also from Wisconsin.* In the years 1 882-1 884, Professor J. C. 

 Arthur was called upon to investigate the cause of the mysterious 

 death of domestic animals in the State of Minnesota, supposed to 

 have resulted from the drinking of water at a time when it was 



* Trelease, Trans. Wis. Acad. Sci. 7 : 121-129. 1888. 



Probably Michigan also should be included, for Campbell mentions " Rivularia 

 echinata Eng. Hot." in a list of plants of the Detroit River (Bull. Torrey Club, 

 13: 93. 1886). 



