1920.] NATURAL SCIENCES OF PHILADELPHIA 101 



This species has been observed only on Spruce Mountain and 

 neighboring ridges in Pendleton County, West Virginia. The soils 

 are upland peats over sandstone rocks, and the reaction is subacid 

 to mediacid. 



Dendrium buxifolium (Berg) Desvaux. 



Habitat. — Moist and occasionally dry sand, and wet sphagnum 

 peat. 



This species has been observed at various places in central and 

 southern New Jersey, being especially prominent in the Pine-barrens. 

 Its soils show in practically every case a mediacid reaction, rarely 

 approaching subacidity. In its typical occurrences in white sand, 

 this acidity appears to be due to the presence of autogenous humus, 

 that is, humus formed by the decomposition of the leaves of the 

 plant itself. 



Kalmia latifolia L. 



Habitat. — Dry upland peat and wet sphagnum peat. 



Acidity. 



5+ ' X 



4 X 



3 X 



2 



1 X 



300 100 30 10 3 1 



The optimum soil reaction of this species is probably subacid, 

 but it is of frequent occurrence in mediacid soils too. The lowest 

 acidity tabulated was noted in upland peat over calcareous glacial 

 drift near Stroudsburg, Pa. Seedlings have been observed most 

 frequently in subacid soils. 



Ka'tnia angustifolia L. 



Habitat. — Wet sphagnum peat, moist and dry upland peat, and 

 dry sand. 



The optimum soil reaction of this species is probably mediacid, 

 but it is also frequently found in subacid soils. In northern New 

 England it is most often met with in mediacid peat, and seedlings 

 have been observed only in such material. Subacid reactions have 



