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and is nowhere very abundant. Tulip-poplar is widely distributed in 

 the southern half of the state, and reaches its best development in the 

 Wabash and Ohio valleys. Sassafras grows everywhere, often in old 

 fields, and very seldom as a large tree. Sweet gum is common 

 throughout the southern bottomlands, and reaches its best develop- 

 ment there. Sycamore is everywhere characteristic of the banks of 

 streams, and reaches enormous dimensions in the Wabash-Ohio basin. 

 The various species of crab, thorn, haw, and plum trees belonging to 

 the three genera, Pynis, Crataegus, and Prunus, never reach large 

 size, and are generally found as an understory to the larger trees. 

 The one exception to this rule is black cherry, which reaches mer- 

 chantable size and forms an appreciable part of the stand in many 

 mixtures, especially in the north. The honey and water locusts occur 

 on the better soils, and sometimes grow large enough to make saw- 

 timber. Black locust, though not in its natural range, has escaped 

 from cultivation and naturalized itself very widely. Ailanthus is an 

 exotic which has been widely planted, and is now growing wild in 

 some localities. Ohio buckeye is fairly common, but not abundant, 

 along the valley sides of the larger rivers, and sometimes on bottoms, 

 while yellow buckeye is comparatively rare. The coffeetree is a widely 

 distributed but infrequent tree, found in much the same situations as 

 the buckeyes. The basswoods or lindens are also throughout the state, 

 but do not often form any great proportion of the stand, except in 

 the north, where in limited localities they grow in fair quantities on 

 some of the bottoms of the smaller streams. Black gum occurs over 

 a greater part of the south and central part of the state, where it often 

 forms an appreciable part of the forests; while tupelo gum, although 

 found in considerable quantities, is confined with cypress to the 

 extreme southern bottoms. The common catalpa (Catalpa catalpa) 

 is a naturalized species, but the hardy catalpa {Catalpa speciosa) is 

 native on the southern bottomlands, where it once attained consider- 

 able size and commercial importance as a post timber. It is now 

 largely used for planting. Pawpaw and persimmon occur commonly as 

 small trees or bushes. The former is more restricted in range than 

 the latter, occurring most abundantly in the southern third of the state. 



Many other species, such as the sumachs, hornbeam, blue beech, 

 witchhazel, redbud, wahoo, dogwood, and viburnums, are found as 

 small trees or bushes that form an understory in the forest. 



The following list shows one hundred and twenty-nine tree species 

 found in Illinois. This number includes a few that are seldom more 

 than bushes. On the other hand, it omits many species of Crataegus, 

 and perhaps a few of Pyrus and Salix that are sometimes classed as 



