THE NORTH AMERICAN SPECIES OF PANICUM. 
By A. S. Hircucock anp AGNES CHASE. 
INTRODUCTION. 
BASIS AND METHODS OF THE WORK. 
The present paper discusses the species of Panicum known to occur 
in North America north of Panama, including the West Indies. The 
results presented are based primarily upon the collections in the 
United States National Herbarium. The collections of Panicum in 
all the large herbaria in this country and in Europe have also been 
examined. In addition to the work done on this large amount of 
herbarium material both authors have carried on for several years 
extensive field studies in all parts of the United States, as is indicated 
by the specimens cited under “Distribution.” A number of species 
of the section Dichanthelium have been grown for several seasons 
in the greenhouse in order to determine the relation between the 
vernal and autumnal forms. 
AMERICAN HERBARIA EXAMINED. 
BitrmMorE, Nortu Caroiina. The Biltmore Herbarium, contain- 
ing the types of most of the grasses published by Chapman in his 
Flora of the Southern States. 
CAMBRIDGE. The Gray Herbarium of Harvard University. 
Cuicaeo, The herbarium of the Field Museum of Natural History. 
New York Ciry. The herbarium of the New York Botanical 
Garden, at Bronx Park. The herbarium of Columbia University, 
which is kept apart from the general herbarium of the Botanical 
Garden, contains the Torrey Herbarium, each sheet of which is appro- 
priately stamped. The private herbarium of Mr. George V. Nash is 
also located at the Botanical Garden. 
PHILADELPHIA. The herbarium of the Academy of Natural 
Sciences of Philadelphia, containing the plants of Nuttall and Buckley 
41616°—vot 15—10——1 
