116 THE I'LAXT WOKLD. 



other by Dr. Chapman), their principal difference being that 

 Querciis lauri folia is evergreen and Q. Pliellos deciduons. (This 

 fact, by the way, is not mentioned by Chapman or Smalh) Tn 

 summer, therefore, it is very diffienlt to distinguish the two 

 species where they are removed from their natural hal)itats. 



Figure 20 show^s a group of these trees photographed in May, 

 in which the one nearest the center, and the one next to it on the 

 left, are Quercus Pliellos, and the others of similar size Q. laiiri- 

 folia. There is nothing remarkable about this ])icture, but in 

 figure 21, wliich shows the same grou]> of trees in winter condi- 

 tion, taken as nearly as possible from the same point, the re- 

 sults of the accidentally enforced competition between the two 

 species are brought out in a striking manner. It will l)c noticed 

 at once that the tree {Q. laurifolia) just to the right of the cen- 

 tral one {Q. Pliellos) seems to ha\'e lost or failed to develop 

 about half its branches, and the impression is 'given that the wil- 

 low oak is crowding the otlier tree aside. That this phenomenon 

 is not a mere accident is shown l)y the fact th.at there are other 

 cases of the same kind in the vicinitv ; thouiili none of the others 

 happened to be so well situated for photographing as this one. 

 The two trees in question are ])resumably of the same age, for 

 they are very nearly of tlie same size, the trunk of Q. Pliellos 

 being thirty-three inches in diameter breast-high, and that of 

 Q. laurifolia thirty-one inches. 



It is hardly possible as yet to explain the exact nature of 

 the competition between these trees, but a few correlations can 

 be pointed out. From the standpoint of succession of vegeta- 

 tion the two species are far apart, Quercus laiirifojia ]>eing a 

 sort of pioneer tree, almost confined to the sandy hammocks of 

 the coastal plain, from Virginia to I-onisiana,'- while Q. Pliellos 

 is a tree of the climax forests, more common in the fertile val- 

 levs and alluvial bottoms of the Palaeozoic region. 



Jn temperate Eastern ^Morth America practically all climax 

 species are shaderloving, while the reverse is true of many if not 



*See Bull. Torrey Club .33:529; Ann. N. Y. Acad. Sci., 17:249, 1906. 



