186 BROOKLYN BOTANIC GARDEN MEMOIRS 



*Facies d. Pine-heath with dominance of grasses. 



*Facies e. Pine-heath with dominance of Vaccinium myrtillus 



and V. vitis-idaea. 

 *Facies/. Pine-heath with bog-moss substratum. 

 2. Type. Broad-leaved Tree-heath. 

 Facies a. Birch-heath. 

 *Facies h. Oak-heath. 

 Those facies of the forest-heaths in Germany which are similar 

 physiognomically with the ones in New Jersey are marked with an 

 asterisk. Facies e in Germany, with the prevalence of two species 

 of Vaccinium, is represented in New Jersey by a pine forest with an 

 undergrowth of Gaylussacia resinosa, Kalmia angustifolia, Vaccinium 

 pennsylvanicum and V. vacillans. The oak-heath we have described 

 and also the heathland, where the bearberry is common, as on Nan- 

 tucket. 



We are able, therefore, by this comparative study to correlate 

 certain American plant formations with those of Europe. The species 

 of plants represented in each are in general different, but physiog- 

 nomically the contrast can be made with general correctness. 



America ' Europe 



Heathland (with huckleberries, bkie- Heathland (Heide, with heather, etc.). 



berries and bearberries, etc.). 

 Oak-heath (with low oaks, etc.). Oak-heath (Eichen-heide). 



Coremal (heathland -with broom-crow- Low pine-heath (Kiefern-heide). 



berry in Nantucket with addition 



of dwarf pine on plains of New 



Jersey). 

 Pine-barrens (Long Island and New Pine-heath (Kiefern-heide). 



Jersey, incipient on Nantucket 



(Figs. 7 and 8)). 



Much remains to be done in the study of the phytogeography of 

 America, but we have reached a stage in our investigations where it 

 is profitable to compare the American plant formations with those of 

 Europe and other parts of the world. This comparison leads to a 

 clarification of our concepts and also brings about a correlation of 

 our knowledge, so that it is possible to formulate certain principles 

 upon such comparative study. The three international phyto- 

 geographic excursions have done much to stimulate this kind of 

 comparative investigation, where the studies of botanists in other 

 climates and in other countries can be used for the extension of our 

 knowledge of the fundamental principles upon which phytogeography, 

 ecology and plant physiology depend. 



