EPIPHYTES 



347 



and the method of attachment. The differences seen above, there- 

 fore, must be explained by the behaviour of the motile reproductive 

 bodies which either come to rest in the depressions or else are 

 swept there by micro-currents in the water. Another interesting 



No, incLhr. 

 120 



100- 



1 2*5 4*5 10 13 15 AbbTox.QjLuxniLty of LndiuLd. jsrcbcnt 



Depth, of alt. Leaves in cins. ^ ^ 



Fig. 201. A, B, distribution of Cocconeis placentula on successive intemodes of 

 plants of Equisetum limosum, well separated (3 stems average). r = Iess than 

 5 individuals per o- 1 sq. mm.; ry = about 5; re = about 10; c = about 30; z;c = about 



50. C, distribution of Cocconeis placentula ( ) and Eunotia pectinata ( ) 



on crowded plants of Equisetum limosum (3 stems average). D, distribution of 



Stigeoclonium sp. ( ) and Coleochaete scutata ( ) on fairly crowded stems 



of Equisetum limosum (2 stems average). E, distribution of total epiphytes on 

 successive leaves of Oenanthe fluviatilis. (After Godward.) 



Epiphyte 



Cocconeis 

 Stigeoclonium sp. 

 Chaetopeltis 

 Ulvella 

 Coleochaete scutata 



Table XX 



No. in scratches No. elsewhere 



517 

 665 

 138 



747 

 40 



297 

 198 



54 



200 



13 



feature is the frequent association of Gomphonerna with the basal 

 cells of Oedogonium, but so far there is no evidence to suggest 

 whether this is a casual relationship or not. Ponds with muddy 

 bottoms have a reduced number of epiphytes probably because the 

 pW and the gases evolved are toxic, but so far little or no work has 



