52 



Trans. Acad. Sci. of St. Louis. 



was only slightly injured on growth 3 years old or over 

 and this injury occurred almost invariably between the 

 flakes or ridges of bark. It has frequently been reported 

 that only moderately severe hailstorms cause a serious 

 malformation and restriction of growth when catalpa 

 pods are developing. Such malformation consists of 

 badly curved pods, many of which fail to develop. Mod- 

 erate hailstorms after the pods are fully developed rarely 

 do serious damage. 



Sycamore suffered co-ordinately with the catalpa in 

 regard to leaf defoliation and very nearly as bad results 

 to the young twigs. The effect was so severe that not a 



HAIL INJURY TO CATALPA. 



single sycamore was seen which had not made an entirely 

 new seasonal growth and often the growth was killed back 

 so that the adventitious buds developed from the middle 

 of last season's growth. Unlike the catalpa, however, the 

 bark on the sycamore shoots 2 years old was not severely 

 injured, but the force of the hail caused slight wounds on 

 the largest trunks. A microscopic examination showed 

 that few of these wounds had affected the cambium badly 

 except in twigs and small branches. 



Eussian mulberry suffered badly from defoliation and 

 injury to new growth. In the usual cases two-thirds to 

 three-fourths of each tree was defoliated while many 

 specimens standing in the open were entirely defoliated. 

 Injury to the bark was nearly as severe as it was to the 



