Notes and Comment. . 3o3 



made in the United States to establish permanent tropical bo- 

 tanical laboratories in this hemisphere, this is the first that has 

 looked to a location which is under the American flag It is 

 doubtful if this somewhat sentimental crnsideratirn will ofTset 

 the much more advantageous natural conditions which char- 

 acterise other localities in contrast with Porto Rico. However, 

 such a station, maintained in connection with the University 

 of Porto Rico, will have great usefulness, especially in researches 

 relating to tropical agriculture. 



\^arioas bulletins of the Bureau of Plant Industry bearing 

 date of 1911 are well worth the attention of botanists. Natural 

 Vegetation as an Indicator of the Capabilities of the Land for 

 Crop Production in the Great Plains Area, by H. L. Shantz 

 (Bui. No. 201), brings out the capital fact that in the area under 

 investigation (eastern Colorado) the general conditions of soil 

 and climate, whether favorable or unfavorable to crop produc- 

 tion, are indicated by the character of the native plant cover. 

 Thus, for example, the land which bears a pure short-grass cover 

 was found to be supplied with water only in the surface foot or 

 two of soil and for a brief period during spring and early sum- 

 mer, while land with a uniform cover of tall grass was found 

 to be supplied with water to a much greater depth and to offer 

 conditions favorable to plant growth during a much longer 

 season. Areas of greatest agricultural value, one year with an- 

 other, are those marked by the presence of wire-grass vegetation. 

 Bunch-grass land is best for crops during very dry years. Short- 

 grass land (grama-buffalo-grass association) produces more 

 than any other type during wet years, but fails in time of drouth. 

 These are but examples of the various correlations between the 

 natural plant cover and the crop-producing capabilities of land 

 in the areas studied, as they are presented by the author. The 

 careful account of plant association, added to determinations 

 of physical conditions, especially with soil moisture and run-off 

 are of much interest to the student of ecology and also indicate 

 something of the great value of such an investigation to the 

 intending settler. — V. M. S. 



