138 ILLINOIS ACADEMY OF SCIENCE 



A careful study of this material succeeded in verifying 125 

 out of the 139 species mentioned in Flagg's list, which includes 

 practically everything mentioned by other authors. 



There are in all, 22 species reported from Illinois of which 

 no authentic material has been seen. Some of these are re- 

 ported in Gray's Manual and Brittain and Brown's Illustrated 

 Flora as occurring in Illinois, but no Illinois specimens are 

 found either in the Gray Herbarium, the New York Botanical 

 Garden, nor the herbarium of the U. S. Department of Ag- 

 riculture. Many of these were plainly wrong determinations, 

 but others may yet be found when more material is examined. 



Of the 125 species mentioned in Flagg's list there are 25 

 species introduced from Europe. My own list at present con- 

 tains 187 species, of which 36 are introduced, making 62 

 species more than have been reported in a State list up to this 

 time, or an increase of 50 per cent. It will perhaps be interest- 

 ing to consider for a moment where these 62 new species have 

 been obtained. As is well known, the majority of species in 

 our Illinois flora belong to genera which are most abundant in 

 warmer climates and of our 151 species native to Illinois, two- 

 thirds belong to genera which are most abundant in the south- 

 east and some are also found in Mexico. Nearly all of our 

 species found in sandy or very dry soil have such an origin, 

 and these, for the most part, are confined to such areas 

 throughout the State. Apparently they have spread from one 

 sand area to another, but of that we have no certain know- 

 ledge. Such are most species of the genera Sporobolus and 

 Aristida, some Panicums, certain Eragrostis species, Triplasis 

 purpurea, Cenchrus carolinianus and many others. Of the 

 remaining third we have a large number which are found all 

 over the eastern United States, such as Andropogon scoparius, 

 Seersia oryzoides, Festuca octoflora and others. In the north- 

 ern part of the State, particularly around the lakes, we have 

 several species which are more abundant to the north of us, 

 such as Phalaris arundinacea, Ammophila arenaria, Bromus 

 Kalmii and others. We have very few typically western forms, 

 probably our Bouteloua species are more so than any others 

 in our grass flora. 



Of these 62 species not included in the earlier lists 9 are 

 species introduced from Europe. These include Bromus in- 

 canus and tectorum, the latter of which is spreading very rap- 

 idly in the State, Lolium tementulum or bearded darnel, Hor- 

 deum nodosum, Panicum miliaceum, the old world millet, 

 Arrhenatherum elatius or tall oat grass, Helochloa schoen- 

 oides and Sorghum halapense or Johnson grass, which has 



