48 UNIVERSITY OF MISSOURI STUDIES [19O 



frequent; Mespilus coccinea, Hypericum proMcum, Rhus aro- 

 matica, and Rhamnus lanceolata are characteristic. The herbs 

 are of semi-xerophytic species; such plants as Antennaria plan- 

 taginifolia, Parthenium mtegrifolium,Comandra umbellata, As- 

 tragalus Mexicanus, and Viola palmata being representatives of 

 a flora, the more xerophytic aspects of which will be considered 

 later. 



The flora of the forest plain, in general, is that typical of 

 the sylva. 



There are, however, north of Columbia two forms of the 

 oak sylva that require brief mention. In the normal oak sylva of 

 the plain the white oak, Quercus alba, is dominant, but as the 

 sylva approaches the prairie or encroaches upon it, the forest 

 first formed is developed naturally from the trees fringing the 

 streams. Later, or partly synchronizing with it, the flora of 

 the normal oak forest makes its way in. Thus it happens that 

 some of the highest land in the region is forested in large part 

 with lowland and riparian trees. The other type of oak forest 

 occurs south and southwestward of the Pinnacles upon soil 

 lighter than any in the immediate vicinity of Columbia, and 

 there the black oaks are dominant. 



iv. Sylvales quercoides ulminae. The elm subassoci- 

 atioii of the oak sylva occupies the region of the coal measures 

 north of Columbia. Besides the elm (Ulmus Americana), the 

 bur oak (Quercus macrocarpa) , the swamp white oak (Q. pla- 

 tanoides), the swamp black oak(Q. palustris), and the red oak 

 (Q. rubra) are common. The white oak (Q. alba) is relatively 

 scarce. The black cherry (Prunus serothia) is frequent, and 

 the juniper (luniperus Virginiarui) is common on the hill 

 slopes. The strictly riparian trees such as the sycamore {PlatOr- 

 nus occidentalis) and the cottonwood (Populus monilifera) are 



