It can be noted that there is a similarity in the proportion of Local Region- 

 al species. It is also interesting to compare the eastern and western marshes 

 of the U.S.A., and also the inland salt marshes of Europe. The Northern Hemi- 

 sphere component of the New Zealand marshes to a large extent consists of 

 aliens. 



II. Degree of Affinity. 



This can be arrived at in various ways and different coefficients 

 have been proposed. For reasons of convenience the Absolute 

 Affinity used by Raabe (1952) has been employed. On this basis a 

 value of over 50 percent indicates a degree of affinity which in- 

 creases as it approaches 100 percent. Three schemes are present- 

 ed showing the absolute affinities of the Puccinellietum maritimae, 

 the Juncetum gerardii, and the Artemisietum maritimi. 



N. 



W. 



North 

 Holland 



(Puce . -Aster 

 communities) 



29.5 



Central Europe 



S. 



Absolute affinities for the Puccinellietum maritimae. 



49 



