22 



Hitchcock and Chase has contributed a goodly number, much in 

 excess of what were named in the older Manuals. As given in 

 that work thirty-three species and one variety, P. Huachucae 

 Ashe var. silvicola Hitch. & Chase, have been detected in the 

 region around the head of Lake Michigan. This is a crescent- 

 shaped area, forty-five to fifty miles wide in its widest part, the 

 horns becoming thinner and approaching the lake on the east 

 side at Grand Beach, Michigan, and on the west side at Zion 

 City, Illinois, near the Wisconsin boundary. I shall not enu- 

 merate the majority of the species, since a reference to that work 

 will give the required information, but give only a few of the 

 more interesting from a distributional point of view. Some 

 have been added since that work appeared and do not find a 

 place on their maps of distribution. All but two of the above 

 number likewise appear in the basin of the Glacial Lake Chicago, 

 or the area once covered by the expansion of the present Lake 

 Michigan when its waters drained southward into the Mississippi. 

 One of these is P. linearifolium Scribn., found at Wheaton, 111. 

 The other, P. Leibergii (Vasey) Scribn., is treated as an exception, 

 since I do not know of its growing in the area at present. In 

 June, 1880, I found it in the sandy ground beside the Rock 

 Island Railroad at Englewood, now within the limits of Chicago. 

 The station was destroyed long since, and its presence there may 

 have been due to introduction, since its present place of growth in 

 our region is in a dry field bordering the railroad just east of 

 Joliet. I was not able to identify it with any form given in the 

 Manuals at that time, and it remained long in the herbarium 

 without a trivial name. On the appearance of Britton & Brown's 

 Illustrated Flora, in 1898, I found in the appendix to the third 

 volume a description and figure which answered the purpose, 

 and the name was applied. This was not my earliest collection 

 of this grass. An examination of my herbarium showed speci- 

 mens of P. Leibergii, but under another name, taken in meadows 

 about five miles south of Preston, Minn., in June, 1869, and in 

 June, 1870, in copses at Waldron, Kankakee County, 111. 



Those added or not given for this region in the work of Hitch- 

 cock and Chase are P. Ashei Pearson, P. microcarpon Muhl. and 



