6 ILLINOIS NATURAL HISTORY SURVEY MANUAL 3 



Wabash and Mississippi rivers, a gradual transformation of 

 this southern flora occurs, but deciduous Holly, Swamp Privet, 

 Silverbell and other species remain to mark its earlier existence 

 as far north as Wabash and Pike counties. 



Usefulness of Shrubs. — Were one to classify wild plants 

 according to man's interest in them, trees probably would rank 

 first, herbs second and shrubs third. For this there is a very 

 practical set of reasons. Trees have been exceedingly important 

 to man, first in providing weapons and shelter, later as material 

 for household equipment, machinery, transportation and beauty. 

 Wild herbs are important because many of them have medicinal 

 values and are serviceable in maintaining or restoring health 

 and because the brilliance of their blossoms adds cheer and 

 beauty to even the dullest of habitations; and cultivated herbs 

 are the sources of man's most important foods. 



The usefulness of shrubs, although less apparent, is in reality 

 great. They do not yield lumber in quantity, but such of them 

 as produce useful wood furnish it as a rule for very special pur- 

 poses. Certain of them have become important in commerce as 

 plants furnishing food; in the main, as is true of grapes, rasp- 

 berries, blackberries, dewberries and hazelnuts, such foods are 

 luxuries rather than necessities. The use of shrubs in beautifi- 

 cation is very extensive, also. Although only a few of them pro- 

 duce the flower splendor exhibited by herbs, their desirability in 

 adornment of habitations has been enhanced by their adaptability 

 for artistic effects in hedges and massed plantings and as speci- 

 men plantings. 



In their native habitat, shrubs furnish shelter, food and cover 

 to woods-loving birds and animals. The beauty of wild shrubs, 

 their usefulness as occasional sources of food and the protection 

 they give to wildlife have long been appreciated and justify 

 more than the usual general interest in their habits, occurrence 

 and distribution. For beauty alone, few things surpass the dog- 

 woods, shadbush and hawthorns in the early spring landscape. 



Purpose of the Manual. — This manual is not a technical 

 contribution to the science of botany but a series of descriptions 

 and illustrations, based on good scientific procedure, intended to 

 be understandable and useful to the nature lover. To this end, 

 descriptions of species cover all the botanical features that a 

 person ordinarily will have need or occasion to notice. They 

 depart from the usual botanical method, however, in two re- 



