VOLUME LXXI NUMBER 3 
THE 
BOTANICAL GAZETTE 
MARCH ro2r 
LEAF SPOTS OF THE ELM 
L. E. MILES 
(WITH PLATES VIII-X AND ONE FIGURE) 
Introduction 
About eighteen species of the genus Ulmus are known (2), 
widely distributed throughout the cold and temperate regions 
of the Northern Hemisphere. Six of these species, U. americana, 
U. fulva, U. racemosa, U. alata, U. serotina, and U. crassifolia, are 
native to America and occur naturally from Labrador to southern 
Mexico. None, however, occur west of the Rocky Mountains. 
U. alata, U. crassifolia, and U. serotina are tender and do not 
grow well in the northern states, but are quite extensively used for 
lawn and avenue trees in the south. U. americana, the most 
widely distributed American species, occurs in practically every 
state east of the Rocky Mountains, and in Canada. It is the 
most characteristic tree of the northeastern states, and is very 
widely used for street planting and as an ornamental tree for lawns. 
Among the fungous enemies of the elm are a number of forms 
which cause leaf spots, the most important of which will be dis- 
cussed in this paper. Ordinarily none of these diseases is of much 
importance economically, but in severe cases they may injure 
the tree materially by causing premature defoliation. This saps 
the vigor of the tree, and if the severe attack is repeated during a 
number of consecutive seasons, may even result in its death, or at 
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