INTRODUCTION. XXII 
crack down which it descended. On the other hand the same 
kind of lava when not affected by rain and wind will remain 
unchanged for centuries, as may be seen under the lee of East 
Maui. Nowhere else have the forests, although extensive, so 
gregarious a character as within the area of Mauna Loa, and the 
species which compose them show hardly any variation from 
those forms which are met with more to the east. The forests 
of Hilo and Hamakua, which belong to the region of Mauna 
Kea, are. already more diversified, and still more those of the 
Kohala range. 
n great contrast stands the vegetation both of Kauai and of 
the Kaala range of Oahu. Most ‘of Mann's and Wawra’s new 
species come from Kauai, and Mr. Knudsen’s collections have 
added still more to them. Even the species which that island 
has in common with others generally vary from them in one or 
more particulars. The Kauai species of the leading Hawaiian 
genera are in all instances the most specialized, to be distinguished 
by more striking characters than the others. Examples are: 
Schiedea, Raillardia, Dubautia, Campylotheca, Lipochaeta, Pittosporum, 
Pelea. The proportion of species peculiar to Kauai with species 
peculiar to all the other islands is about 67 : 382, or 17.5 : 100. 
For the sake of convenience the Hawaiian flora may be 
divided into groups occupying different zones of elevation, as 
follows. 
The lowland zone. Open country, grass-covered after the 
rains, with isolated trees or clumps of trees eager by 
Paritium tiliaceum, Erythrina, Reynoldsia, Pandanus, Capparis, 
Gossypium, Abutilon incanum. It also includes the Hittoral Foe. 
The lower forest-zone. Tropical in character, its upper limit 
between 1000 and 2000 ft. above the sea. Its physiognomy is 
marked distinctly by Aleurites Moluccana, the pale foliage of 
which in contrast with the green color around attracts at once 
the eye of the beholder. The woods are rather open. Zingiber 
Zerumbet covers the ground. Cordyline, Eugenia domestica, Zingiber 
Zerumbet, and other plants are strictly confined to it. Pandanus 
odoratissimus and Paritium tiliaceum do not pass beyond it, but 
Freycinetia does. To its upper portion, but extending into the 
lower portion of the next zone, belong also most Sapotaceae, 
Apocynaceae, Gardenia, enccvenge nora most Urticaceae, annie 
Elaeocarpus, Aurantiaceae, an 
3. The middle forest-zone. This lies within the region of 
clouds, and develops the greatest luxuriance in trees and jungle. 
