LUTHER BURBANK 



rather for their timber, and we have dealt with 

 them when we spoke of forest trees. 



There is a considerable company of trees of less 

 hardy character that nevertheless are resistant 

 enough to thrive in the streets, parks and gardens 

 of our northern States if given a certain amount of 

 protection, even though some of them could not 

 make their way in the wilds in competition with 

 the hardy tribes just mentioned. 



These trees are less hardy than the others, 

 presumably because they migrated a little more 

 rapidly in the old days of changing climates, and 

 kept far enough away from the ice sheet to be able 

 to retain something of their taste for tropical con- 

 ditions. They not only retained the broad leaf 

 system, but some of them also retained or devel- 

 oped the habit of bearing handsome flowers a 

 habit that would have served small purpose for 

 the conifers, since insects could not thrive in cold 

 regions where they remained to battle with the 

 elements. 



Doubtless the most interesting of these trees 

 that escaped destruction by flight, and the one that 

 has maintained most fixedly the traditions of the 

 Mesozoic era is the tulip tree (Liriodendron) . 



This beautiful tree, with its unique broad 

 glossy leaves and handsome flowers is now the 

 lone representative of its genus. One species alone 



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