462 MINNESOTA BOTANICAL STUDIES 



of limited groui)s of plants, others accounts of the flora of particu- 

 lar parts of the state. These lists have varied much in the critical 

 character of the work and are therefore of quite uneciual value. In 

 view of these facts it is not surprising that the standard floras for 

 the eastern part of North America, Gray's Manual, Britton's Man- 

 ual and Britton and Brown's Illustrated Flora, contain many erro- 

 neous statements concerning the occurrence of sj^ecies in Minnesota. 



During the years since the appearance of Upham's Catalogue, a 

 great amount of Minnesota material has accumulated in the Her- 

 barium of the University of Minnesota, and it has become possible 

 to check over the published lists and to correct many of the errors 

 contained in them. As the time does not yet- seem ripe for a com- 

 plete Flora of the state, the authors of the present paper have 

 deemed it advisable to publish a checking-out list of those plants 

 which appear to have been erroneously reported in this state. 



Naturally, the evidence varies much in different species. In the 

 case of some of the plants reported by Upham, and of practically 

 all of those included in later lists, the original specimens are at 

 hand and have been re-examined. In other cases, although there is 

 no direct evidence of the original collections, it appears from abun- 

 dant herbarium material that certain species have been habitually 

 misdetermined by collectors. In still other cases, the evidence is 

 entirely negative, — merely the fact that in over thirty years of more 

 or less continuous collecting in the state no specimen of the species 

 in question has found its way into the Herbarium of the University. 

 These last cases differ considerably in value for various reasons. 

 Obviously a small and inconspicuous species of Car ex might be over- 

 looked by collectors more readily than some large Cypripedium or 

 Liliiim. The authors of this list have endeavored to make clear in 

 each case the evidence upon which their report is based. As they 

 recognize that this evidence is largely negative and therefore incon- 

 clusive, they will particularly welcome authentic reports of the oc- 

 currence of any of these species in the state of Minnesota ; especially 

 will they be pleased to receive information from any of the other 

 herbaria of the country regarding the occurrence of any of these 

 species either in this state, or in its immediate vicinity. In return 

 they will always be glad to furnish other workers with reports of 

 the occurrence or distribution of species in Minnesota, based upon 

 the collections in this Herbarium. 



