HITCHCOCK AND CHASE — NORTH AMERICAN PANICUM. 9 



States or countries, the States being in the sequence followed by 

 the Century Atks, the other countries and provinces being inter- 

 polated or added with the intention of preserving the general sequence 

 from north to south. Mexico and Central America precede the West 

 Indies. The islands of Tobago and Trinidad are considered as 

 belonging geographically to South America and are listed after 

 Venezuela. All specimens cited in the distribution or mentioned in 

 the notes are in the United States National Herbarium unless other- 

 wise stated. Specimens from other herbaria are cited from States or 

 countries when such specimens add to the known range or fill in gaps 

 in the listed distribution. In such cases only one specimen is men- 

 tioned from each additional State, unless the species is rare or of 

 peculiar distribution. These additions are taken from other herbaria 

 in the following order: Hitchcock's herbarium, Gray Herbarium, 

 herbarium of the Academy of Philadelphia, herbarium of the Mis- 

 souri Botanical Garden, Biltmore Herbarium, herbarium of the Field 

 Museum, the herbarium of the New England Botanical Club, and 

 other local herbaria in no particular sequence. 



In order to save space, specimens are cited by collector and number 

 only, or, if the collector's number is not given, the year is stated. a 

 This method makes clear in most cases the identity of the specimens 

 listed. It must be borne in mind that when a specimen is cited by 

 the collector's number it refers to the particular sheet in the National 

 Herbarium or other herbarium mentioned. It not infrequently 

 occurs that two or more species, collected at the same time and place, 

 or collected at different times and places but supposed by the collec- 

 tor to be the same species, are distributed under the same number to 

 different herbaria. Collectors have in some cases sent to the National 

 Herbarium a set of grasses for identification, and later distributed 

 other sets in which the species under certain numbers were different 

 from those submitted for names. This is especially misleading if the 

 labels state that the sets have been determined at the National 

 Herbarium or the Department of Agriculture or by a specialist whose 

 name appears upon the label. The numbered sets collected by 

 Charles Wright in Cuba, which contain many examples of more than 

 one species distributed under one number, have been discussed in an 

 earlier publication. b 



The locality cited in the distribution does not always exactly agree 

 with that given on the label. Occasionally, for convenience, several 

 specimens from the same general locality are listed under one head- 

 ing; for instance, " Vicinity of Cape Henry" may include specimens 

 labeled " Virginia Beach" or "Lynn Haven." This has not often 



a Smith 1900 indicates that the specimen is Smith's number 1900; Smith in 1900 

 indicates that the specimen was collected by Smith in the year 1900. 

 & Hitchcock, Contr. Nat. Herb. 12: 185. 1909. 



