LIST OF PLATES 
Frontispiece. A Brazilian forest interior, showing lianas ascend- 
ing trees and some air plants perched on roots and also on the 
slanting tree trunk at the right. 
Facing page 
Prats I. Aérial roots of an orchid. A typical air-plant; the roots 
serve as holdfasts and also absorb water that trickles over them 
during rains. : : : : : . 
Pirate I. Excurrent trunks of European cypress (Cupressus seni- 
pervirens) 
Pvare IIL. Deliquescent trunks of olive. The vigorous life of the 
trees, in spite of the extent to which the trunks have become hol- 
lowed by decay, illustrates the unimportance of the heartwood 
except to stiffen the trunk against winds . F 
Prare LV. Group of date palms, showing the comparatively cylin- 
drical form of the stems, their unbranched mode of growth, and 
the rough remains of broken-off leaf-stalks along the trunks. 
Prare V. Pollarded poplars. These have been cut back to furnish 
a crop of twigs for withes, used in binding grapevines to their 
supports. The twigs may spring from dormant or from adven- 
titious buds ‘ 3 a : ‘ 
Piate VI. Exposure of leaves to sunlight. The morning-glory 
shown is not the common kind, but a European species (Phar- 
bitis Learii). Some of the stems are climbing a wall which faces 
west, others lie flat on the ground. The leaves of the former 
stand with their upper surfaces facing nearly west, those of the 
latter with the upper faces nearly vertical, in both cases secur- 
ing abundant sunlight 
Puatre VIL A eat-tail swamp. The plant is an aquatie with aérial 
leaves. The season selected for the picture is that when the 
downy ripened fruits are beginning to be wafted away by the 
wind . é . : . : 5 : 2 , 2 
viii 
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oO 
or) 
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