100 PROCEEDINGS OF THE ACADEMY OF [March, 



Azalea arborescens ?iirsli. 



Habitat. — Moist upland peat. 



This species has been observed in the mountains of eastern cen- 

 tral West Virginia, chiefly in Tucker county. The soil is moist 

 upland peat, and the usual reaction subacid. 



Azalea viscosa L. (including varieties glauca, nitida, etc.) 



Habitat. — Wet sphagnum peat and occasionally dry upland peat 

 at swamp margins. 



The optimum soil reaction for this species is mediacid. The lower 

 values noted represent places where the plant pushes out from its 

 usual swamp habitat into dry sandy woods. The n in the table 

 refers to Gillett's nursery at Southw^ck, Massachusetts. This 

 makes with the preceding plant a pair of closely related species with 

 marked dissimilarity in optimum soil reaction. 



Rhododendron maximum L. 



Habitat. — Moist and occasionally dry upland peat and wet sphag- 

 num peat. 



Acidity. — 



5+ X 



4 



3 X 



2 XX 



1 X X " 



300 100 30-10 3 1 



The optimum soil reaction for this species appears to subacid, 

 but its range is unusually wide. The most acid reaction tabulated 

 represents occurrences in sphagnum peat in a swamp in central 

 Lycoming County, Pa., and in moist upland peat in the mountains 

 of West Virginia. The two least acid values were observed in upland 

 peat on calcareous glacial drift east of Williamsport, Pa. While 

 some of the roots of these plants were found to be surrounded by 

 soils of these acidities, other roots of the same plants were in subacid 

 soils. Seedlings have been found most frequently in subacid soils. 



Menziesia pilosa (Michaux) Persoon. 



Habitat. — Dry and occasionally moist upland peat. 



