THE PALAEOTROPICS 257 



tial rains to the windward side of the islands, while the lee sides 

 may be very dry. Where the mountains are low, as in Oahu, the 

 rain may pass over the crest and fall at the head of the valleys on 

 the lee side. An annual rainfall of 500 inches has been recorded 

 from a station in Kauai. 



The lowlands are closely cultivated, sugar and pineapples being 

 grown on a very large scale, as well as the usual tropical fruits; 

 and in some localities rice is grown. 



Most of the vegetation seen about Honolulu and the other towns 

 is exotic, and a great variety of beautiful flowering trees and shrubs 

 is cultivated. The two commonest trees, the "algaroba" (Proso- 

 pis sp.) and " iron-wood (Casuarina equiseti folia) , are both in- 

 troduced, but have become completely naturalized. 



The strand-vegetation includes such wide-spread types as 

 Hibiscus tiliaceus, Ipomoea pes-caprae, Scaevola, Pandanus, 

 Calophyllum — all familiar strand-plants of the eastern tropics; 

 but the strand-flora as a whole is not an extensive one. 



The commonest trees of the lowland forest, where it has sur- 

 vived, are two — the "Kukri" or "candle-nut" (Aleurites Moluc- 

 cana), and the "mountain-apple" (Eugenia Malaccensis). As both 

 of these are wide-spread in Malaysia and are of considerable eco- 

 nomic value, it is thought that they may have been introduced 

 by the early immigrants from the South Seas. 



The upper forest zone, on the windward side of the islands, is 

 a pronounced rain-forest with dense growth and many epiphytes; 

 but lianas are not abundant, the most important being a climbing 

 screw-pine, Freycinetia Arnotti. The most abundant tree of the 

 upland forest is Metrosideros polymorpha, a near relative of the 

 New Zealand rata. The showy red flowers are a great attrac- 

 tion to the honey-sucking birds of the peculiar Hawaiian family 

 Drepaninidae. Another important tree is the "Koa" (Acacia 

 Koa), much resembling some of the Australian species. 



The trees and shrubs of the lower forest zone are largely genera 

 common to the eastern tropics and Australia, but absent from 

 America. Among these may be mentioned Pittosporum, ( lardenia, 

 Coprosma, Metrosideros, Santalum, Dracaena. The ferns and 

 liverworts show a remarkable number of species identical or closely 

 related to those of the Malayan-Australasian area. 



There are a good many endemic Hawaiian genera, e. g., Platy- 



