1920.] NATURAL SCIENCES OF PHILADELPHIA. 107 



Vaccinium vacillans Kalm. 



Habitat. — Dry and occasionally moist upland peat. 



Acidity. — 



5+ X 



4 X 



3 



2 X X XX 



1 



300 100 30 10 



The optimum soil reaction of this species is subacid. The least 

 acid reaction tabulated, actual neutrality, was observed in Lancas- 

 ter County, Pa., at the contact of sandstone and limestone forma- 

 tions, this species extending over onto the limestone. At other 

 contacts it is one of the earliest of the Ericaceae to appear as the 

 limestone is receded from. 



Vaccinium corjnmbosum L. 



Habitat. — Wet sphagnum peat and moist and occasionally dry 

 upland peat. 



Acidity. — 



5+ X X 



4 



3 X 



2 X 



1 X 



300 100 30 10 3 1 



The optimum soil reaction of this species is probably subacid, 

 although it is common in mediacid soils as well. The lowest acidi- 

 ties tabulated were observed in the Lehigh Valley west of Allentown, 

 Pa., in upland peat on glacial drift overlying limestone. 



Vaccinium ai.rococciun (A. Gray) Heller. 



Habitat. — Wet sphagnum peat and moist and occasionally dry 

 upland peat. 



Acidity. — 

 5+ 

 4 



3 XX 

 2 



1 X X X 



300 100 30 10 3 1 



The optimum soil reaction of this species is probably subacid. 

 The lowest acidity tabulated was observed in upland peat on glacial 

 drift overlying limestone in the Lehigh Valley west of Allentown, 

 Pa. 



