1910] Book Review 219 
and American herbaria. In the extent to which Hitchcock and Chase 
have borrowed and determined the collections belonging to smaller 
institutions and to individuals, they have set an example which other 
monographers may well follow. Few professional botanists have 
any idea of the stimulus which can thus be given to botanical col- 
lecting and exploration. 
The monograph covers all America north of Panama, including 
the West Indies. In this area the authors recognize 205 species and 
subspecies, although they exclude from Panicum a number of outlying 
groups, which are better treated as generically distinct. It gives one 
faith in the serviceability of the authors’ species-concept to know that 
they have been able to place, definitely, with no evasion and no side- 
tracking, a mass of material numbering many thousands of sheets. 
Yet the work contains only 16 new species and subspecies. To most 
botanists the treatment might have been made a trifle more satis- 
factory if certain varieties and forms, which are informally defined, 
with citation of specimens, had been named instead of treated as 
" exceptional specimens." 
A feature which deserves the highest praise is the full discussion, 
under each species, of the synonyms which are referred to it. Prof. 
Hitchcock has studied practi 'ally every extant specimen of American 
Panicum, which has ever been designated as a type, or can be con- 
strued as a type. The result is a surprisingly short list of “ Doubtful 
Species" and a critical commentary on the synonymy which will be 
of great use to future students. In this connection it may be noted 
that misapplied names (7. e., published errors in determination) are 
given no nomenclatorial standing. 
The description of each species is accompanied by two text-figures, 
an enlarged spikelet and a map showing, roughly, the geographic 
range in the United States. In nearly every case the spikelets have 
been drawn from type or authentic material, and are thus of permanent 
value as standards for comparison, regardless of what difference of 
opinion may ever arise in regard to the delimitation of groups or the 
identity of particular specimens. It is unfortunate that the press- 
work at the Government Printing Office was not of a high enough 
order to make the most of Mrs. Chase's beautiful figures. The maps 
are not as useful as they would have been if the dots had always been 
placed so as to indicate precise localities. A dot placed in the center 
of a state is used frequently to indicate a general distribution of the 
species In that state. 
In the citation of specimens the authors have been unusually 
liberal. They have not only cited specimens under each species, to 
show the geographic range, but they have also prepared an index to 
numbered specimens which will prove one of the best features of the 
book. 
The treatment of the dichotomous Panica (under the newly named 
subgenus Dichanthelium Hitchcock & Chase) is painstaking in the ex- 
