26 Trans. Acad. Sci. of St. Louis. 



unfolded for many weeks and many were still unfolding. In 

 accounts of the injuries sustained by trees in former storms, 

 little is said of leaves and leaf injuries. The manner in which 

 leaves are attached to stems enables them to present the 

 smallest surface to the wind, and thus to escape injury. 

 Peculiarities in the structure of leaves have been adduced as 

 another protecting factor.* When moist, leaves are far more 

 liable to injury than when dry ; several leaves cling together, 

 and the force of the wind pounds and rubs them against twigs 

 and branches, tearing and lacerating them.f In the present 

 -case the destruction of foliage was very marked, particularly 

 in such trees as the soft maples and sycamores ; several trees 

 of the honey locust retained most of their leaves. For a 

 large area about the trees, some minutes after the storm, the 

 ground was covered with torn and shredded leaves of all 

 kinds. The leaves were wet, for it had been raining for sev- 

 eral minutes before the windstorm, and the injuries evidently 

 were largely due to rubbing against branches. Flying missiles 

 of various kinds aided in the destruction. Grains of sand 

 and small bits of wood and stone, flying through the air at 

 velocities ranging from 50 to 80 miles per hour, were well able 

 to shred the tender leaves. As a result of these combined 

 causes many maples and sycamores were left with hardly a 

 sound leaf on the remaining branches. 



Besides the injuries to the branches and leaves there were 

 others not so evident at first. Numerous trees had trunks of 

 sufficient elasticity to bend before the force of the wind, with- 

 out breaking. In swaying to and fro, the bark on one side 

 was considerably stretched, and compressed on the opposite 

 side, and in the next instant the conditions were reversed. 

 Where this took place repeatedly the bark was torn horizon- 

 tally for several feet, sometimes on but one side, more often 

 on both. The violent wrenching of a tree with a large top 



* Kny, L. Uber die Anpassung der Laubbliitter an die mechanischen 

 Wirkungen des Regens und Hagels. Berichte d. deutsch. Bot. Gesellschaft 

 3: 207. 1885. 



f Magnus, P. Verhandl. d. Botanischen Ver. d. Prov. Brandenburg 18: 

 viii. 1876. — Caspary, R. Beschadigung der Rosskastanienblatter durch 

 Reibung mittelst Wind. Botanische Zeitung 27 : 201. 1869. 



