MESOPHYTES 855 
In the Alleghany region and New England the upland 
forests are very extensive and complicated, grading from 
the rich flood-plain forests of the lower levels to the strictly 
xerophytic forests (pines and black oaks) of the higher lev- 
els, and dominated by various oaks, chestnuts, and hick- 
ories. 
The flood-plain forests of New England are not so rich 
as those of the Alleghany region and the central West, the 
dominant forms being elm, 
linden, ash, maple, syca- 
more, tulip-tree, ete. 
215. Tropical forests. — 
The forests of the rainy 
tropics may be regarded as 
the climax of the world’s 
vegetation (Fig. 319), for 
the conditions favor con- 
stant plant activity at 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. 
The striking characteris- 
tics of the great mixed trop- 
Fiq. 320.—A gutter-pointed leaf of a rainy 
tropical forest.—After ScHIMPER. 
ical forest are as follows: (1) There is no regular period for 
the development or fall of leaves, and hence there is no time 
