1921] PALMER, BOTANICAL RECONNAISSANCE OF SOUTHERN ILLINOIS 143 



of which there was a small crop this year, it appears to be the combina- 

 tion given above. 



Quercus borealis var. maxima X imhricaria = Q. runcinata Engclm. A 

 medium-sized tree with abundant fruit was found on the edge of a bit of 

 upland wood near Simpson, Johnson County. Both supposed parent 

 sj)ecies, as well as Quercus velutina^ Q. Shumardii var. Schneckii and Q. 

 rubra, were growing nearby. 



Quercus imhricaria X marilandica = Q. tridentala Engclm. A single tree 

 of this supposed hybrid was seen on the grounds of Dr. Robert Ridgway, 

 at Olney, Richland County, where it was first discovered by him, 



Quercus paluslris X Phcllos. An unmistakable hybrid between these 

 two species is rather frequent in low swampy woods about Cairo and 

 Mound City, where the two parent species grow in close proximity. In 

 that vicinity the hybrid was almost as common as the Willow Oak. This 

 hybrid was also found near Brookport, Massac County, and at Wickliffe, 

 Kentucky. It was not found fruiting at any station, 



Quercus phellos X velutiua. A small tree, suspected to be this hybrid, 

 was found in low woods, bordering a swampy lake, near Miller City, 

 Alexander County. There was no fruit. 



Ulmus americana L. Rather abundant throughout, and found in all 

 sorts of situations except deep swamps. 



Ulmus fulva Michx. Apparently absent from the Cairo Formation; 

 most abundant in upland woods of the Mounds Formation and occa- 

 sionally found along bluffs and steep hillsides in the Ozark region. 



Ulmus alala Michx. More or less abundant throughout, but com- 

 monest in the Ozark region and northward. A form with branchlets 

 entirely destitute of the characteristic corky wings is frequent. 



Celtis occidentalis var. canina (Raf.) Sarg. Occasionally found in low but 

 seldom inundated bottoms of the Cairo Formation, Apparently rare or 

 absent from the uplands of the Ozark Ridge, but commoner northward 

 in the Ohio and Wabash valleys. 



Celtis occidentalis var. crassijolia (Lam.) Gray. About as common 

 as the last, and in similar situations. Most abundant north of the Ozark 



Ridge. 



Celtis laevigata Willd. Abundant in low woods, especially in the Cairo 

 Formation; rare or absent from the Ozark Ridge region. 



Celtis pumila var. georgiana (Small) Sarg. A shrub or rarely a small 

 tree along rocky banks and bluffs in the Ozark Ridge region. Seen in 

 Johnson, Pope and Hardin Counties, and doubtless occurring through- 

 out the rocky uplands. 



Celtis pumila var. Deamii Sarg. Of similar habit, and found in like 



situations as the last. 



Morus rubra L. Found sparingly throughout the region; most com- 

 mon in the upper alluvial lands of the Cairo Formation. Much sought for 

 post timber on account of its durability. 



