MONOBLEFH ARID ALES 83 



MONOBLEPHARIDALES 



The Order Monoblepharidales includes a small number of 

 aquatic fungi of rather unique characteristics, the outstanding of 

 which is that in sexual reproduction a large non-motile t^g is 

 fertilized by a small motile antherozoid. This situation is un- 

 known elsewhere among the filamentous fungi. Asexual repro- 

 duction throughout the group is accomplished by means of zoo- 

 sporangia producing uniciliate zoospores. In this order the cell 

 walls do not turn blue with zinc chloroiodide, an indication of 

 the absence of cellulose. 



Monoblepharis, the largest genus and the one most completely 

 known, contains about eight species, the first of which was de- 

 scribed by Cornu (1871) in France. The characteristics of 

 Monoblepharis are so different from those of other phycomyce- 

 tous fungi that some doubt as to the existence of these forms 

 remained in the minds of most mycologists until Thaxter (1895) 

 rediscovered representatives of the group in America. Shortly 

 thereafter, as the result of the studies of Lagerheim (1900) in 

 Sweden and Woronin (1904) in Finland, Monoblepharis became 

 better known. The most recent monograph of the group is that 

 of Sparrow (1933). - 



Monoblepharis is found most frequently on dead submerged 

 twigs in quiet, clear, fresh-water pools. The genus appears to 

 have been found most often in cool waters, early in spring, in 

 the countries of northern Europe and in the northeastern United 

 States. It is seldom recognized in the field but will develop 

 readily when the twigs are placed in aquarium jars in the labora- 

 tory. In cool waters (8 to 11° C) only sporangia will develop; 

 higher temperatures (21° C) are required for the production of 

 sexual organs. The tufts of delicate hyphae protruding from 

 the lenticels of the twists consist of a rhizoidal system, which 

 anchors the plant to the substratum, and a series of slender 

 branches. The protoplasmic contents of the hyphae include regu- 

 larly arranged vacuoles and oil globules, which impart a charac- 

 teristic foamy appearance to the hyphae. 



The sporangia are borne terminally, containing a single row 

 of zoospores, and are cylindrical, to spherical, to more or less 



