98 BOTANICAL GAZETTE [AUGUST 
1. Littoral—(a) Humid littoral, along the windward coasts; 
(6) arid or semiarid, along leeward coasts and coasts far removed 
from the mountainous interior. 
2. Lowlands.—Up to tooo-1500 ft., with humid and arid sec- 
tions, depending upon relation of topography to trade winds and 
distance from interior mountains. 
3. Forest zone.—(a) Lower forest (1000-2000 ft.), with humid 
and arid sections; in early times this zone extended much farther 
seaward on the various islands than it does now; (6) middle forest 
Fic. 2—View from a dividing ridge between 2 long humid valleys, looking 
toward the head of Kau-kona-hua Valley; fog-covered summit ridge, elevation 2500 
ft., seen in distance; entire region covered with dense and unbroken rain forest; on 
slopes and ridges trees average 15-30 ft. in height, in valley and ravines they rise 
to 40-6o ft.; annual precipitation at head of this valley approximates 200-300 inches. 
(1800-5000 ft.), range variable, with humid and arid sections; this 
comprises in the humid areas the typical Hawaiian rain forest, 
highly hygrophytic and very rich in endemic forms; (c) upper forest 
(s000-go00 ft.), restricted to the high mountains of Maui and 
Hawaii. 
4. Summit regions.—(a) Xerophytic summits (gooo—14,000 ft.); 
high mountains of Maui and Hawaii; (0) hygrophytic summits 
: rine it}; peaks rising into the cloud zone, with summit bogs. 
