LIST OF PLATES 



Frontispiece. Pine sap, or false beech drops (Monotropa Rypop- 



itys), a saprophytic seed-plant without chlorophyll, and with 



scales instead of foliage leaves. 



Facing page 



Plate I. Aerial roots of a hanyan tree. This tree, a species of 

 Ficus, usually begins its life as a seedling in the crown of a palm 

 tree. It soon sends slender roots to the earth, and as these 

 penetrate the soil the banyan grows rapidly and soon destroys 

 the palm. A banyan tree has been known to cover with its 

 columnar roots a diameter of three hundred feet and reach a 

 height of eighty feet in seventy-five years, from the seed . . 30 



Plate II. Cocoa palms, showing the nearly cylindrical form of the 

 stems, their unbranched mode of growth, and the leafy crown 

 at the summit of the stem 66 



Plate III. Pollarded poplars, showing growth of slender twigs 



from dormant or from adventitious buds .... 96 



Plate IV. Japanese ivy, a tendril climber, showing an irregular 

 set of leaf-mosaics, each leaf arranged at the most advantageous 

 angle for the reception of sunlight 106 



Plate V. An opening in a tropical forest, showing dense vegeta- 

 tion due to heat and moisture. Aerial roots abound. The 

 forest floor in the foreground is covered with shade plants 

 whose broad leaves fully utilize the light supply . . . 114 



Plate VI. A California desert with a tree yucca {Clistoyucca 

 arborescens) in the foreground. This is one of the most con- 

 spicuous xerophytes of the deserts of the extreme southwestern 

 United States 118 



Plate VII. American mistletoe, parasitic on a Cottonwood tree. 

 The photograph is taken in winter, so that all the foliage shown 

 is that of the parasite 138 



Plate VIII. American cypress {Taxodium), a hydrophyte. The 

 conical " cypress-knees " in the foreground are outgrowths from 

 the roots, supposed by some to absorb oxygen and convey it to 



the submerged roots 140 



viii 



