Dutch elm disease fungus (cf, U.S.D.A. Circular, op cite, No. 
ETE, yee 100). 
The Augustine Ascending Elm shows a resistance to these 
diseases. Only by repeated graftings of diseased patches of elm 
wood onto the trunks of young Augustine Ascending Elms, potted 
and growing in greenhouses, can they be killed. We do not 
know of a single Augustine Ascending Elm, transplanted 
successfully from our nursery and growing in the open, which 
has succumbed to either of these two elm plagues. 
In the Spring of 1949, nine young Augustine Ascending 
Elms were sent to the State Natural History Survey Division 
at the University of Illinois in Urbana. In the greenhouses they 
were potted, and an attempt was made to graft onto their trunks 
wood from elms having phloem necrosis. The grafts did not 
“take,” and the trees continued in a thriving condition. Attempts 
were made again in July, 1950 to graft diseased wood onto the 
trees, and one of the trees died. Again in the Fall of 1950 and 
in the Spring of 1951, the Division tried to graft onto the trunks 
of the Augustine Ascending Elms; but none of the grafts to this 
date (August, 1951) have taken, and all the trees are in excel- 
lent condition. So the results of these tests are equivocable. 
Six young Augustine Ascending Elms in the Spring of 1949 
were sent to the United States Department of Agriculture’s 
Bureau of Plant Industry, Division of Forest Pathology, in 
Columbus, Ohio. In the Spring of the following year, Dutch elm 
disease resistance tests were started; and in August of the same 
year, Dr. Roger Swingle, Senior Pathologist, reported that “the 
Augustine Ascending Elm is susceptible to Dutch elm disease.” 
The particulars of the tests have not been made available to us. 
Even if the trees were to be killed by successful grafting of 
diseased wood onto their trunks, it would not prove that an 
Augustine Ascending Elm growing in a natural situation had no 
resistance to disease. For the thick, rough leaf of the Augustine 
Ascending Elm seems, from the Association’s field experience, to 
be repugnant to insect carriers. But from results of laboratory 
testing by direct innoculation, we cannot definitely claim that 
the Augustine Ascending Elm is immune to elm disease. It seems 
justified, however, to claim for it a resistance to phloem necrosis 
and to point to field experience for testimony about its resistance 
to Dutch elm disease. 
For letters from the owners of this mutant American Elm 
testify, without exception, to its vigorous growth and continuing 
health. It was stated above that not one Augustine Ascending 
Elm growing in natural conditions is known by the Association 
to have succumbed to either of the two elm plagues. Evidence of 
the tree’s vigor is given below by quoting passages of letters 
received from owners of Augustine Ascending Elms. 
TESTIMONIES 
In the late Autumn of 1949 the City of New York, Depart- 
ment of Parks, received 200, two-year-old Augustine Ascending 
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