426 JOURNAL OF FORESTRY 



teries of nature as revealed in the phenomena of plant life. It is im- 

 possible, however, to know plants as living things or to comprehend 

 the great truths about them unless we know what sort of plant it is that 

 has excited our wonderment. Just as we love our fellow creatures 

 as individuals with names, so we must be able to identify the tree 

 before we can enter into any closer relationship. 



The Genera of Grasses in the United States, with Special Reference 

 to Economic Species. By A. S. Hitchcock, Systematic Agrostologist. 

 U. S. Department of Agriculture, Bui. 772. Contribution from the 

 Bureau of Plant Industry. 1920. Pp. 307. 



All genera of grasses are described that embrace native, introduced, 

 or cultivated species in the United States. Under each genus reference 

 is made to the type species and to species of economic importance, both 

 useful and harmful plants. The economic consideration takes into 

 account the grasses that are used for hay or pasture purposes, for 

 cereal and sugar production, those used in broom and paper making, 

 and the ornamental species. Throughout the paper the word "grass" 

 is used strictly in its botanical sense ; that is, as applying only to the 

 plants of the family Poaceae or Gramineac. 



The keys to the tribes and genera are arranged in a simple, workable 

 way, and these, together with an illuminating half natural size photo- 

 graph or sketch of a representative species under each genus, should 

 enable the amateur botanist readily to fix in his mind the generic char- 

 acteristics, and, indeed, the species typifying the genus. A brief of the 

 publication of each generic name is given and the reason is stated for 

 choosing the species taken as a type. 



The arrangement of the material, in general, differs from that of 

 previous contributions on the subject in that the tribes have been placed 

 in a new sequence based upon the complicity of the flower structure, 

 the simplest or most primitive being placed first and the most highly 

 developed being given last. According to the author's researches, the 

 tribal arrangement as presented is the closest approximation to the 

 natural relationship that can be shown in sequence. Accordingly, the 

 bamboos (Bambosece) are listed first, as certain genera embraced in 

 this tribe are of the simplest floral structure. 



The following points are of special interest to agrostologists : 



Munroa has been placed under the tribe Chloridece. 



