224 BOTANICAL GAZETTE. 



olivaceo. — In locis grarninosis, circa Lehigh University, Bethle- 

 hem, Pa. E. A. Rau, Oct. 24, J 882. 



The photographs of this new Phallus were made by Dr. C. 

 L. Loch man, Bethlehem, who has for several years past made 

 excellent .photographs of a number of the most important indi- 

 genous and exotic medicinal plants. — Eugene A. Rau, Bethle- 

 hem, Pa. 



Notes on Fresh -Water Algje. 



In relation to species of Algae which produce what the Ger- 

 mans call " wasser-bliithe," or, in less poetical English, a scum 

 on the surface of bodies of water which serve as water-supplies, 

 there has of late been felt a great interest on the part of the pub- 

 lic, and in this connection I would call attention to some inter- 

 esting forms found in Minnesota last summer by Prof. J. C. Ar- 

 thur. The two scum plants, so common in the Eastern States, 

 Clathrocystis aeruginosa, Henfrey, and Coelosphoerium Kuetz- 

 ingianum, Nag , appear to be also common in the West and were 

 found by Prof, Arthur in Lake Satakah and Lake Tetonka, at 

 Waterville, Minn.; and the first-named species "was also found by 

 Prof. Wm. Trelease in Lake Mendota, Wis. Consequently, as 

 the West becomes more thickly settled we may expect to bear of 

 the same disagreeable pig-pen odor which is found in Eastern 

 water-supplies during hot summers. 



Prof. Arthur also detected an interesting alga floating on 

 Lake Tetonka, Waterville, and Lake Phalen, near St. Paul, 

 which has not as yet been found in Eastern water-supplies. 

 The alga in question resembles Rivularia aira, Roth, but is of 

 softer consistency and the filaments have a different micrometric 

 measurement. The species of Rivularia grow attached to other 

 plants, sticks, stones, etc. , and although they at length become 

 free, they are then found resting loosely on the bottom and not 

 forming a scum on the surface of the water. In Hedwigia, Jan., 

 1878, Cohn described a Rivularia which he called R. fiuitans, 

 which formed a " wasser-bliithe " on the river Leba, near Lauen- 

 berg, in Pomerania; and in Hedwigia, March, 1878, Gohi men- 

 tioned the occurence of a similar Rivularia at Udrias, on the 

 Gulf of Finland, to which he gave the name of R. flos-aquce; 

 but in Hedwigia, April, 1878, he stated that his plant was of the 

 same species as that of Cohn. The Rivularia collected by Prof. 

 Arthur in all essential respects seemed to me to be the same species- 



