SAPROLEGNIALES 1 7 1 



gators since de Bary. (v. Minden, 1912: 533.) Two additional 

 species isolated from the soil, L. subterranea Coker & Harvey 

 (Harvey, 1925: 158) and L.eccentrica Coker (1927: 215) have been 

 recently described. 



Doubtful Genus 



Jaraia Nemec (1913). 



This very imperfectly understood genus is known only from 

 the original paper of Nemec. It was based by him on a single 

 species, J. salicis Nemec, isolated from enlargements on hving 

 roots of Salix, and is regarded by him as an undoubted member 

 of this family. The sporangia and oogonia are extremely 

 irregular in form. The sporangia are provided with several exit 

 tubes. The oogonia are many-spored. Further study will be 

 necessary before the relationships of the form are clearly under- 

 stood. It is placed in the Blastocladiaceae by Gaumann (1926: 

 58). 



Leptomitaceae 



This relatively small family, embracing approximately fifteen 

 species in six genera, includes such a wide diversity of forms 

 that doubt to its phylogenetic unity will probably arise in the 

 mind of the student. The members of the group agree, never- 

 theless, in several seemingly essential respects. Their mem- 

 branes are of cellulose, their zoospores are biciliate, and their 

 hyphae are quite definitely and characteristically constricted. 

 As a result of the presence of the constrictions the hyphae have a 

 segmented appearance. Strongly refractive granules of cellulin, 

 a carbohydrate material probably allied to cellulose, are present 

 in the protoplasm and provide one of the most characteristic 

 features of the group. These granules are especially prominent 

 near the constrictions, and at times pass into them forming 

 definite plugs with the aspect of thick septa. This occurs 

 particularly in the cutting off of the sporangia and sexual organs. 

 Later the plugs may disappear. True septa are not formed. In 

 the genus Gonapodya wholly similar constrictions and cellulin 

 plugs occur, and by some authors the genus is incorporated 

 in this family. A consideration of all the characters of the 

 genus indicates that it is intermediate in type between the 

 Leptomitaceae and Blastocladiaceae, and in the present treat- 

 ment it is placed in the latter family on account of its non- 



