INTRODUCTION. 9 



Care and identification of material. The identification, dis- 

 tribution and arrangement of all the phanerogamic and vascular 

 material collected during the season of 1891 was put in charge 

 of Mr. E. P. Sheldon, whose ability and aptness for the work 

 have been an indispensible assistance to the author. Under the 

 direction of Mr. Sheldon, Mr. W. D. Frost and Mr. A. P. Anderson 

 gave some time to the mounting and arrangement of such 

 plants as were reserved for the general herbarium. This work 

 occupied the entire autumn of 1891 and the winter and part of 

 the spring of 1892. The large collections in the herbarium of 

 the Department of Botany, which numbers not far from 62,000 

 specimens, afforded excellent facilities for comparison when 

 -critical forms were under consideration. A few doubtful forms 

 have been submitted to specialists, but in no cases have the 

 determinations of Mr. Sheldon been modified. 



Citation of herbarium specimens. Every plant in the herba- 

 rium of the survey is known by its collector's name followed by 

 a serial number. It thus becomes possible to refer to any plant 

 definitely and decisively. Any mistakes in identification, if 

 such should by chance occur, would thus be easily discovered 

 and corrected by future workers. Under each species in the 

 subsequent list of Metaspermae occurring native in the Minne- 

 sota valley, all the herbarium material at hand is entered. Not 

 only is the Minnesota valley material properly inserted, but all 

 Minnesota specimens receive their place under the appropriate 

 heads. Only such Minnesota specimens as belong to species 

 not known or believed to occur in the drainage basin of the 

 Minnesota river are excluded. In this way a complete account 

 of the status of each species, in the herbarium, is presented to 

 students throughout the state, and gaps or poorly represented 

 species may receive attention from future collectors. 



In addition to the citation of all Minnesota specimens of 

 Minnesota plants, so far as represented in the herbariums of 

 the University, citations have been made from the personal 

 collections of Mr. Sheldon, Mr. Wickersheim, of Idlewild, 

 Lincoln county, and Judge Moyer, of Montevideo, gentlemen 

 who have kindly contributed by the loan of their herbaria to 

 our knowledge of the limits of species in their districts. The 

 collection of Mr. Sheldon, cited as Herb. Sheld., is principally 

 from the Ft. Snelling district ; that of Judge Moyer, cited as 

 Herb. Moyer, from the mouth of the Chippewa river ; that of 

 Mr. Wickersheim, cited as Herb. Wickersheim, from Lincoln 



