348 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 



ILLUSTRATIVE MATERIAL. 



Field studies have brought together sufficient material in the group 

 to warrant the distribution of a set of specimens illustrating the 

 writer's conception of the species. These sets, so far as material is 

 available, are deposited in the leading accessible consulting herbaria. 



A total of nine sets have been put up and deposited as follows: 



United States National Herbarium, Washington, 1). C. 



Gray Herbarium, Cambridge, Mass. 



New York Botanical Garden, New York City. 



Missouri Botanical Garden, St. Louis, Mo. 



Field Museum of Natural History, Chicago, 111. 



University of California, Berkeley, Cal. 



Koyal Botanic Gardens, Kew, England. 



Koniglicher Botanischer Garten, Dahlem-Steglitz bei Berlin, Germany. 



Museum d'Histoire Naturelle, Paris, France. 



Beginning on page 425 will be found a list of the species which are 

 being thus distributed, together with designation of the sources of 

 the material. The types of the new species here proposed are con- 

 tained in the set deposited in the United States National Herbarium 

 at Washington. In some cases the numbers are distributed under 

 other names than those of the text because they were arranged before 

 the work on the text was completed. 



LIMITATION OF THE GENERA. 



The genus Bouteloua a was established by Mariano Lagasca in 

 Variedades de Ciencias, Literatura y Artes (Madrid) in 1805. So 

 far as I am able to determine he has expressed in no way what species 

 he considers typical of the genus, although an elaborate discus- 

 sion is given of the characters and of the economic importance of the 

 group as pasture grasses. Apparently the only way of fixing the 

 type of the genus is to choose the first species listed. This method 

 is as usual the most easily applied in fixing the generic type, and 

 under the application of this rule the name Bouteloua wall have to 

 stand for the genus, however that genus is limited, containing the 

 first species, Bouteloua racemosa Lag., which is clearly the same spe- 

 cies as the earlier described Chloris curtipendula Miclix. Lagasca 

 wrote another and more comprehensive treatise upon the same genus 

 eleven years later, in winch B. hirsuta is the first species listed and 

 B. racemosa the last. In this treatise Lagasca again fails to indicate 

 what he considers the type of his genus. However, the application 

 to the 1805 paper of this arbitrary principle of priority of place is not 

 here considered to be at all affected by the subsequent publication. 



a Originally this was written Botelua, although Lagasca states that it is dedicated 

 to two Spanish gardeners, brothers, of the name of Boutelou. In a later paper (Gen. 

 & Sp. Nov. 1816) he adopts the spelling used here. 



