1921] PALMER, BOTANICAL RECONNAISSANCE OF SOUTHERN ILLINOIS 141 



Ostrya virginiana (Mill.) K. Koch. Rather abundant on rocky hill- 

 sides in the Mounds Formation, and sometimes found along rocky bluffs 

 and stream banks in the Ozark region; but apparently absent from the 



Cairo Formation. 



Carpinus caroliniana Walt. More or less abundant in low woods and 

 on alluvial banks of streams throughout; most abundant in the Mounds 

 and Cairo Formations. 



Betiila nigra L. Frequent on alluvial stream banks throughout the 



region. 



Alnus rugosa (DuRoi) Spreng. Seen only in Johnson County, along 



rocky stream banks. 



Fagus grandifolia Ehrh. Rarely found in rich woods, on knolls and 

 slight elevations in the Cairo Formation, and in deep hollows and below 

 high bluffs in the Ozark region. Much commoner in the Mounds For- 

 mation where it is a characteristic tree. 



grandifolia var. caroliniana (Lo 



Grow- 



ing in similar situations as the species, and perhaps more abundant. 



Quercus alba L. A common Oak in many places and rather abundant 

 throughout. Most frequent and of the largest size in the Mounds For- 

 mation. 



Quercus stellata Wang. Common in the rocky upland woods of the 

 Ozark region, and occasionally found throughout, except in the swamps 

 and low bottoms of the Cairo Formation, 



Quercus hjrata Walt. An abundant and characteristic species of the 

 low and swampy lands of the Cairo Formation. Noted in Alexander, 

 Union, Pulaski, Massac, Gallatin, Johnson, Jackson, Saline, White, Wa- 

 bash and Richland Counties. 



Quercus macrocarpa Michx. Occasional throughout, but nowhere very 

 common. Most abundant in bottoms of the Cairo Formation, and else- 

 where found along alluvial flood plains of most of the streams. 



Quercus hicolor Willd. Abundant in low woods throughout. A typical 

 tree of the low lands and semi-swampy areas. More common north- 

 ward. 



Quercus Prinus L. A species of the low woods; most abundant in the 



Cairo Formation, but less common than Q, lyrata. Seen in Alexander, 

 Pulaski, Union, Jackson, Johnson, Massac, Gallatin, White and Wabash 

 Counties, and reported by Dr. Ridgway from Richland County. 



Quercus Muhlenhergii Engelm. Most abundant in the limestone areas 

 of Union, Pope and Hardin Counties, but found occasionally along bluffs 

 and banks in the Mounds and Ozark Ridge Formations. 



Quercus rubra L. A common Oak of the low but not swampy woods 

 in the Cairo Formation, and perhaps equally common in the Mounds 

 Formation, where it often becomes a very large tree. In the Ozark 

 region it is comparatively rare. This is Quercus falcata Mic! 



Quercus palustris Moench. A very common species in the lowlands 

 of the Cairo Formation, and abundant throughout along streams. 



