1920.] NATURAL SCIENCES OF PHILADELPHIA. 117 



The ebony spleenwort, Asplenium platyneuron, which is usually- 

 found in soils of but moderate acidity, grows in all the vegetation 

 areas of sputhern New Jersey. In the Pine-barren and Coastal 

 ■ones, however, it is found only on steep banks, where the acidity 

 may be rather lower than in level places. The oak fern, Phe- 

 gopteris {Dryopteris) dryopteris, a plant characteristic of cool shaded 

 places- where the soils are circumneutral, would hardly be expected 

 to become established in the warm climate of southern New Jersey. 

 But that its spores actually reach this region is shown by the oc- 

 currence of a colony in an old well in the Pine-barren area, where 

 the combination of low acidity and cool atmosphere is of course 

 attained. 



In the paper above cited, as well as in studies in other regions. Dr. 

 R. M. Harper has used the percentage of evergreen — chiefly coni- 

 ferous — trees as an index of the relative poorness in salts of the soils 

 of individual vegetation-areas. • While a relation of this sort un- 

 doubtedly exists, it would be a mistake to infer from it that all 

 conifers are alike in their soil requirements. The pitch pine, Pinus 

 rigida, thrives in the salt-poor mediacid soils of the Pine-barren 

 area.; but the scrub pine, P. virginiana, is very rare in that area, ap- 

 parently requiring subacid soil reaction and moderate salt content 

 such as are present in the Marl area. The yellow pine, P. echinata, 

 which is intermediate inits characters between the two others, appears 

 to be relatively indifferent as to soil conditions, and grows about 

 equally well in the Pine-barrens and the Marl area. 



The Canada lily, Lilium canadense, elsewhere a circumneutral 

 soil species, grows in southern New Jersey, as would be expected, 

 • only in the Marl area. The related turk's-cap lily, L. superbum, 

 which seems to be partial to highly acid soils, is on the other hand 

 widespread in southern New Jersey, and most abundant in the 

 Pine-barren area. In the bog near Lindenwold, famous for its 

 remarkable flora, both of these lilies grow, which might be taken as 

 evidence that they are not particularly different in their soil acidity 

 requirements after all. But actual observation shows that the 

 first species grows chiefly at the lower levels in the bog, where Cre- 

 taceous strata outcrop and the soils are circumneutral, while the 

 second occurs higher, in the highly acid soils derived from the Pen- 

 sauken sand. 



Among orchids many species are partial to highly acid soils, aild 

 are in southern New Jersey most abundant in the Pine-barren area. 

 -In the genus Hahenaria, subgenus Blephariglottis, the three species 



