Celtis pumila Pursh, with Notes on allied Species 



By E. J. Hill 



(With Plate 33) 



Since 1889 I have had under observation the species of Celtis 

 which grow in this vicinity — C. occidentalis L. and the one that gen- 

 erally goes under the varietal name of pumila A. Gray, regarded 

 as the equivalent of Celtis pumila Pursh. Since finding the latter 

 in 1893 the impression of their difference and the title of the latter 

 to specific distinction have increased until at last I am convinced it 

 should be restored to the rank assigned it by Pursh. This con- 

 clusion was communicated to Dr. N. L. Britton in a letter, July 

 19, 1899. Celtis occidentalis is a forest tree, here mostly found by 

 the banks of streams or contiguous to them and is most common 

 by the Desplaines River. It also occurs in the lower or more 

 swampy sand region at the head of Lake Michigan, where it is 

 seen sparingly on low sand ridges which border or divide from 

 each other the shallow lakelets near the boundary of Indiana and 

 Illinois. Celtis pumila is found in the dry dune region and is 

 confined to a narrow belt extending east and west of the mouth of 

 the Grand Calumet in Indiana, not yet seen beyond half a mile 

 from Lake Michigan. A full description will be given of C. 

 pumila alone ; only points of comparison between C pumila and 

 other species of the genus need be added. 



Celtis pumila Pursh 



A bushy straggling shrub, 0.75-4 m. high, often in clumps as 

 broad as high, sometimes with ascending stems 4-5 m. long and 

 8-10 cm. in diameter. Branches divaricate or much divergent, 

 usually making a wide angle with their support, often a right angle 

 or even slightly directed downward. They are scraggy, abun- 

 dantly furnished with short twigs 3-10 cm. long, which frequently 

 end in a stiff, leafless, thorn-like point, due to winter killing, and 

 giving them the appearance of a thorn-bush. The bark is thin, 

 gray, smooth or a little roughened at the base. The new branch - 



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