168 



From the first six tables an interested person can work out in 

 a few hours the relative abundance of the species (or groups of 

 related species) in different regions, and other phytogeographical 

 data, such as are not yet available for many other parts of the 

 countn.-. This the reviewer has done, with the results set forth 

 below. As the county is the unit of area in the statistics one 

 cannot follow natural boundaries very closely, and thus an ele- 

 ment of inaccurac}' is introduced, which makes- it hardty worth 

 while to give the computed percentages for each species or group 

 of species. In each of the following five regional lists the com- 

 moner species or genera are arranged in order of abundance as 

 determined from the statistics, and the names of those which are 

 more abundant in a given region than in the other four are 

 printed in small capitals, which gives an additional basis for com- 

 parison without using any more words. Those whose percentages 

 fall below i are omitted in most cases. 



In the northern driftless region, typified by Jo Daviess County 

 (and better by a number of neighboring counties in Wisconsin), 

 thirteen per cent of the area was estimated by Hall and Ingall 

 to be wooded, with an average timber stand of 805 cubic feet 

 per acre; and 13 per cent of the forest is in bottoms and 87 per 

 cent on uplands. (According to the 1910 census 17 per cent of 

 the farm land in Jo Daviess County was woods, which would 

 make 15.2 per cent of the total area even if all the land outside 

 of farms was destitute of trees.) The commonest trees seem to 

 be QuERCUS VELUTIXA and other black oaks, Quercus alba and 

 other* white oaks, Ulmus americana, Quercus ]macrocarpa, 

 Hicoria spp., Tilia americana, Acer saccharinum, Salix spp., 

 Betula LENTA, AcER Saccharum, Juglans NIGRA, Fraximis 

 spp., Populus deltoides, P. tremuloides? , and Platanus occidentalis. 

 The various oaks make up about 56 per cent of the total. 



On the west side of the state there is a small area south of the 

 terminal moraine, including Calhoun County (almost the only 

 one in Illinois without a railroad) and part of Pike. According 

 to Hall and Ingall only 12 per cent of the area of these counties 

 was covered with forest (but the census enumerators about the 

 same time found 20 per cent of the farm land wooded, which 



