THE ELM, PLANER AND HACKBERRY 147 



could not attain such a distribution in the world of today, but 

 absolutely nothing is known of its geological history. 



The family splits sharply into two groups: those in which the 

 fruit is dry and winged, as in the elms, and is distributed by the 

 wind; and the other in which the fruit is more or less pulpy, or a 

 drupe, with a bony stone, and is distributed by birds and mammals, 

 as in the hackberry — the flesh being the attraction, and the stone 

 with its contained seed passing uninjured through their alimentary 

 tract, and discharged properly fertihzed, often at a great distance 

 from the parent tree. The winged fruits of the common elm, as 

 everyone knows, mature in the spring and are immediately shed, 

 usually sprouting the same season, whereas the hackberry fruits 

 ripen in the autumn and do not sprout until the following season. 



All three of the types of trees to which this chapter is devoted 

 have their chief utility as shade trees, although one of the hack- 

 berries is useful in many other ways when planted in our semi arid 

 plains country, and some are extensively lumbered in some regions. 

 Their chief blessing may be said then to be largely aesthetic. One 

 cannot observe a row of elms without being impressed with the 

 beauty of trees and how poor the world would be without them, 

 and if it is true, as some botanists assert, that the herbaceous plants 

 are more efficient than trees and will as time goes on gradually 

 replace the forests, we can rejoice that this process will require 

 milHons of years. I suspect that if we lived in an arid region we 

 would venerate the trees as the Arab does the palm; certainly I 

 know nothing so attractive as forests after one has spent a few 

 months in a desert. The wood of both the elm and the hackberry 

 is marked by wavy or zigzag lines of minute pores when viewed in 

 cross sections of the trunk, a character not seen in the wood of any 

 other of our forest trees. 



THE ELMS 



Elms are widely distributed throughout the North Temperate 

 Zone, except in western North America. They extend southward 

 as far as Mexico in the New, and to the Sikkim Himalayas in the 

 Old World, both of these occurrences at the southern limit of 



