A new record for Leptomitus from Alaska 

 George S. Tulloch 



The purpose of this paper is to report an extension of the 

 geographic range of Leptomitus lacteus (Roth) Agardh. to 

 Alaska and to describe its habitat in this region of the world. 



During July 1931 masses of a fibrous, grayish and slimy sub- 

 stance were collected around placer mining operations along 

 Coldstream Creek near Fox, Alaska (64°55' north latitude, 

 148°41' west longitude). This material was identified as Lep- 

 tomitus lacteus. Later this identification was verified by Dr. 

 Arthur Kevorkian and Professor W. C. Coker. More recently 

 Dr. Kevorkian has studied the zoospore formation in this 

 Alaskan material. The results of his investigations will appear 

 shortly under the title of Studies in the Leptomitaceae. 



This occurrence of Leptomitus lacteus within one hundred 

 miles of the Arctic Circle is a new location which is considerably 

 farther north than any of the previously reported cases. It has 

 been collected many times throughout Europe and North 

 America, yet no northern location has been recorded which is 

 comparable to this record from Alaska. As examples of its north- 

 ern distribution in North America there are the records of 

 Humphrey (1893) from Massachusetts and Connecticut and 

 those of Kevorkian (unpublished) from Massachusetts and 

 Rhode Island. In Europe it has been collected in many places; 

 the records of Corny (1872) and Radais (1898) from France, 

 Kolkwitz (1903), Tiegs (1919) and Amelung (1931) from Ger- 

 many, and Petersen (1911) are cited as examples of its distribu- 

 tion there. The records from Denmark appear to be the most 

 northern of those found in the literature but even these are in a 

 general latitude about ten degrees south of the Alaskan location. 



Leptomitus lacteus is one of the Leptomitales which are com- 

 monly referred to as water moulds. In general the fungi of this 

 order are more or less abundant in all fresh waters, preferring 

 waters which are clear and relatively pure. Leptomitus lacteus, 

 however differs rather strikingly from the other members of its 

 group in preferring a habitat containing large amounts of or- 

 ganic substances such as the slime from sewers or in sewage-con- 

 taminated streams. It has also been reported from drains of 



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