36 Rhodora [Marcu 
these limits lie fairly close together, but also that for different species 
the limits have characteristically different positions in the scale. 
When these points are considered, in connection with the fact that in 
many cases a given species grows under the most widely varying 
physical conditions, from the wettest bogs to the driest sandy up- 
lands, the conclusion can hardly be avoided that the chemical fea- 
tures of the soil are of greater significance than the physical ones in 
determining the distribution of these plants. 
It has been found that in certain nurseries ericaceous plants can 
be grown in soils with an initial acidity distinctly below the lowest 
limits observed for the same species in nature. This is no doubt due 
partly to the exclusion of competition and partly to the fact that 
vigorous plants develop increased acidity immediately around their 
roots. However this may be, the limiting reactions shown by the 
soils supporting each species in its natural habitats are well worth de- 
termining. It is not claimed that the soil reaction is the only factor 
controling the distribution of these plants; nor is the manner in 
which the reaction affects the plant considered. The aim of this 
paper is essentially to record observational data as to the reactions 
shown by the soils in typical natural occurrences of Ericaceae. It is 
hoped that these data can be supplemented by future work in other 
regions. 
The regions in which the studies have been made, the general fea- 
tures of the soils there, etc., are presented in Table II. Detailed de- 
scriptions of the distribution of plants and soils follow. 
TABLE II. FEATURES or REGIONS STUDIED., 
SURFACE DoMINANT 
REGION State FORMATION Soi. Reaction ERICACEAE 
Summits of White Moun- 
IEEE ou hes ey NIMM. Gneliss, Black al- Mediacid Abundant 
granite pine peat 
Mountains — hionóeeg! 
by Lake. Vt. Calcareous Upland Circum- Rare 
drift peat neutral 
Swamps, etc., one of ies 
loughby Lake. si Vt. Calcareous Peat and Subacid Common 
drift muck 
Bog south of West Burke.. Vt. erg Peat Mediacid Abundant _ 
rift 
Swamps, = é zn i-r nei 
and Fairlee, Vt. Varied Peat and Subacid Common 
drift muck 
Grateful acknowledgment is herewith made to Miss Inez A. 
Howe, of the Fairbanks Museum, St. Johnsbury, and to Rev. Dr. H. 
