INTRODUCTION 17 



modiophorales, Lagenidiales, and the Peronosporales have marine re- 

 presentatives. Too little is as yet known about marine Phycomycetes 

 to make any generalizations about their occurrence. Most of those thus 

 far discovered belong to the Saprolegniales and the Lagenidiales. They 

 are for the most part chiefly chytrid-like forms living in algae. A few 

 are members of the uniflagellate groups but the presence of these in 

 the sea is apparently rare in comparison with their occurrence in fresh 

 water. 



The work of Sorgel (1941), of Harder (1939b, 1948, 1954), and of 

 Harder's students Remy (1948), Reinboldt (1951), and Gaertner (1954b, 

 c) makes it abundantly clear that true chytrids are as common in soils 

 as are the saprolegniaceous and pythiaceous forms earlier noted by 

 Butler (1907), Harvey (1925, 1927, 1928), and others. It quickly be- 

 comes apparent to anyone investigating soil Phycomycetes that species 

 of such genera as Rhizophlyctis and Pythium are well-nigh ubiquitous. 

 In West Indian soils, Sorgel (1941) noted that species of these two gen- 

 era, as well as of Nowakowskiella and various mucors, were the chief 

 constituents of the phycomycetous flora; other species constituted less 

 than 20 per cent. Soil from plots in contact with man or domestic 

 animals had more fungi than that from undisturbed regions, and moist 

 sites were more favorable than dry. A small area might support many 

 different kinds of Phycomycetes and depth played no essential role in 

 limiting the fungous content of the soil. Furthermore, distribution 

 throughout an area was fairly uniform. 



Harder 1 (1948) collected soils in Germany from various types of habi- 

 tats, such as shores, ditches, woods, roads, fields, gardens, pastures, 

 meadows, and uncultivated land, and recorded the frequency of occur- 

 rence of certain genera of Phycomycetes. As Sorgel had observed for 

 the West Indies, Nowakowskiella and Rhizophlyctis headed the list 

 and disturbed land had the richest flora. Remy (1948) also worked with 

 German soils. She found the two genera mentioned, together with 

 Rhizophydium, were most frequent. Only three of her 144 samples were 

 completely free of phycomycetous fungi. Disturbed land and moist 

 habitats again proved most prolific and loam was more favored than 

 sand. Her work revealed no particular relationship between frequency 

 of occurrence and soil acidity. Remy also noted that some of the com- 



1 See also Harder and Uebelmesser in Arch. f. MikrobioL, 31 : 82. 1958. 



