500 



SECTIONAL TRANSACTIONS.— K. 



The following table gives a summary of the distribution of the species 

 so far studied : 



The Mycetozoa have not been personally studied and the records are 

 taken from the list published by Miss G. Lister in the Glamorgan County 

 History. Those groups marked with an asterisk have not yet been critically 

 studied and the numbers given represent only incidental records. 



Miss E. Morgan. — The phycomycete flora of Glamorgan ; the Sapro- 

 legniales, especially the terrestrial forms (3.0). 



During 1934-1936, members of the Saprolegniaceae were isolated from 

 soil samples taken from stations in wet pasture, dry pasture and gardens, 

 in two districts of Glamorganshire. 



Nine species of Saprolegnia were identified, and four species of Isoachlya. 

 These species were on the whole more frequent in wet pasture than in dry 

 pasture or garden soils. 



Nine species of Achlya were found. These were more frequently isolated 

 from soils of dry pasture than the species of Saprolegnia. 



Certain species with monoplanetic spores, e.g., Pythiopsis Humphreyana, 

 Thraustotheca clavata, were more common in dry than in wet pasture. 

 These results suggest a connection between spore behaviour and the 

 distribution of species. 



Temperature also seems to be a contributing factor in distribution. 

 Some species are characteristic of spring months, others of summer and 

 others of autumn or winter months. 



There are indications that water and soil may be alternative media for 

 certain species, e.g. Saprolegnia lapponica was abundant in water in July, 

 but reached its highest frequency in soil in April and May. 



Neither humus content nor acidity is apparently as important in deter- 

 mining species distribution as the two factors, temperature and water 

 content. 



