288 



ELEMENTARY STUDIES IN BOTANY 



maple, gum, etc. Deciduous forests may be roughly grouped 

 also as upland and flood-plain (river bottom) forests, the for- 

 mer being less luxuriant and containing fewer types, the lat- 

 ter being the highest type of forest growth in its region. 



The forests of the rainy tropics, called rainy tropical 

 forests, may be regarded as the climax of the world's vegeta- 

 tion (Fig. 238), for the conditions favor constant plant 



FIG. 238. A tropical forest. Photograph by LAND near Xalapa, Mexico. 



activity a the highest possible pressure. Such great forest 

 growths are found within the region of the trade-winds, 

 where there is heavy rainfall, great heat, and very rich soil, 

 as in the East Indies, and along the Amazon and its tributaries. 

 So abundant is the precipitation that the air is often saturated 

 and the plants drip with the moisture. In a great mixed 

 tropical forest there is no regular period for the development 

 or fall of leaves, and hence there is no time of bare forests 

 or of forests just putting out leaves. Leaves are continually 

 being shed and formed, but the trees always appear in full 



