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 f. Pine-heath with bog-moss substratum. 
2. Type. Broad-leaved Tree-heath. 
Facies a. Birch-heath. 
*Facies b. 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 
FHleathland (with huckleberries, blue- 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 (Wiefern-heide). 
berry in Nantucket with addition 
of dwarf pine on plains of New 
Jersey). 
Pine-barrens (Long Island and New Pine-heath (Wiefern-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. 
