30 



The descriptions of vegetation cannot be adequately sum- 

 marized in a brief review, but must be seen to be appreciated. 

 For each of the habitats, about fifteen in number, the environ- 

 mental factors are described in a general way, and the commoner 

 plants listed (usually about one third of the vascular species and 

 sometimes a few mosses and lichens), usually in approximate 

 order of abundance or conspi^^usness, but often disconnectedly, 

 and with a somewhat arbitrary distinction between dominant 

 and secondary species. At the beginning of most of the habitat 

 lists the names of one or two species regarded as dominant are 

 printed in small capitals ; the rest being in italics. (The method of 

 treatment is not very well explained in the paper itself, but some 

 of the facts given in this paragraph have been obtained subse- 

 quently by correspondence with the author.) 



Some valuable original suggestions are made about the critical 

 environmental factors for certain species, but some of these do 

 not seem to hold throughout the ranges of the species. For 

 example, on pages 270 and 283 it is stated that Betula lenta 

 requires a constant supply of water near the surface. But in 

 Massachusetts, New York and Michigan it grows in ordinary 

 "mesophytic" upland woods, and at its southern limits in the 

 mountains of Georgia and Alabama it is chiefly confined to ex- 

 posed clifTs at high elevations (often with Kalmia latijolia). On 

 page 283 Kalmia latijolia is said to be " preeminently a sun-loving 

 plant"; but it grows in dense shade always in Florida, often in 

 North Carolina, and sometimes in Massachusetts. (For both of 

 these species protection from fire is probably a more important 

 factor than soil moisture or insolation.) 



Very interesting is the suggestion on pages 283-286 and 290-292 

 that evergreen herbs are confined to places where they are not 

 crowded by other plants or liable to be smothered by falling 

 leaves. It has seemed to the reviewer, however, that such herbs 

 are especially characteristic of soils poor in potassium and pretty 

 well protected from fire* (this is especially manifest in the case of 

 epiphytes, all of which seem to be evergreenf) ; but at the same 



* See Bull. Torrey Club 38: 517. 1911;41:214-217. 1914. 

 t See Ann. N. Y. Acad. Sci. 17: 38. 1906. 



