lower forest region. In these restricted areas one may find from 40 to 50 
species of trees, some of which are confined to one locality only. It is in these 
places that the writer has found many new species of trees and rediscovered 
some which were thought to have become extinct. Of course, most of the Ha- 
walian plant genera have representatives in both wet and dry districts, which 
differ so greatly from each other that one cannot help coming to the conclusion 
that they must have originated in different periods, meaning that their evolution 
was not carried on simultaneously. 
The Kukui is sparingly represented in these floral districts and is replaced 
by the araliaceous Reynoldsia sandwicensis, a striking tree of sometimes 50 feet 
in height. (See plate VII.) It is one of the trees which possesses a soft wood 
and an exceedingly thin bark. Its most plentiful associate is the leguminous 
Erythrina monosperma, the Wiliwili of the natives, whose wood is also very 
light and soft 
Nearly all Hawaiian Araliaceae come into this region, with the exception of 
a very few species, such as Tetraplasandra Waialealae, the Oahuan varieties of 
T. meiandra, Cheirodendron platyphyllum, and Pterotropia gymnocarpa, which 
are characteristic of the rain forest. Pterotropia dipyrena is peculiar to the 
region discussed in this chapter, though sometimes going over into the middle 
forest zone, to which Pterotropia Kavaiensis, a handsome tree found only on the 
island of Kauai, is peculiar. 
The Apocynaceae have three arborescent species represented, Rauwolfia sand- 
wicensis (Hao), either a shrub or more often a tree, and Ochrosia sandwicensis 
(Holei), not uncommon, and Pteralyria macrocarpa (Kaulu), only found on 
Oahu in the valley of Makaleha. The latter is a small tree, with large, bright 
red, double fruits. The Gynopogon oliviformis (Maile), also belonging to this 
family, has a variety myrtillifolia oceuring in the dry forests, usually climbing 
over trees, and sometimes strangling them to death. 
The most common tree is the liliaceous Dracaena aurea, or Halapepe of the 
natives. It is entirely restricted to this region and only very rarely is found 
outside of it. 
These dry or mixed forest regions oceur, however, in other tropical countries, 
as in East Java and India, and are peculiar in so far as they are composed of 
periodically deciduous trees. In Hawaii only three or four species lose their 
leaves in the dry season, as Erythrina monosperma, Reynoldsia sandwicensis, 
Kokia drynariodes, and Sapindus saponaria. The same may be said of No- 
thocestrum, which also sheds its leaves, but without ever becoming leafiess, as 
its defoliation immediately precedes its acquisition of new foliage. These dry, 
forest regions or mixed woodlands have hardly ever been investigated, previous 
explorers confining their investigations to the wet forests, which appear from a 
distance much more promising. These rain forests, however, display much less 
variety than the mixed forest, where not a single tree species can be called domi- 
nant. Of course, there are exceptions, as for example in South Kona, on Hawaii, 
17 
