AMERICAN NATURALIST 
VOLS VEIL June, 1894. 33° 
THE MEANING OF TREE-LIFE. 
By Henry L. CLARKE. 
Few there are, even among thoughtful botanists, who 
“seem to clearly realize how broad a lesson on the life-history 
of plants is written in the trees that make the great forest 
regions of the world. Whether we stand among the palms of 
the tropics, or the pines of the north, or the congeners of the 
poplar and oak, we feel instinctively that there isan impressive 
depth of meaning in the very aspect of a tree. And itis no 
deception of the fancy. Tree-life represents the culmination 
m the work of one of the two great factors, reproductive 
energy and vegetative energy, that together shape the course 
of plant-development. The history of plants records a con- 
stant two-fold struggle; on the one hand the effort of plant- 
life as a whole to perpetuate itself by improving its methods of 
reproduction; on the other, the stand for self-preservation 
made by each distinct individual or species or group,—a 
Stand that can be taken only through sheer force of vegetative 
luxuriance. But these two phases of the struggle for existence 
ve by no means been independent of each other; they 
have acted together in varying ratio in the making of 
- every type, though their respective influences have culminated 
_ M widely separated forms. As the highest outcome of evolu- 
_ onary progress in the character of floral organs we point to 
3 "University of Chicago. 
31 
