the entrance divides into two main valleys, the vegetation becomes more inter- 

 esting, a few Compositae cling to the rocks, such as Artemisia, and to the writer 's 

 surprise, he found the interesting lobelioideous Brighamia insignis growing on 

 the vertical clififs, even inaccessible to the multitude of goats inhabiting this 

 region. 



On the bottom, at the very head of the gulch, are huge trees of Aleurites mo- 

 luccana (Kukni) (see Plate XXVI), the trunks of some of which are torn into 

 shreds by huge boulders which are constantly coming down from the heights 

 above, which, when loosened by the goats, bring with them avalanches of rocks 

 to the depths below. Nahoku gulch is the narrowest and steepest, and is void of 

 vegetation, but in the early days enough water came down in the now dried-up 

 streambed for the natives to carry on the cultivation of taro. 



The Island of Kahoolawe is the most eroded of the whole group and the only 

 native tree growth which remains is composed of perhaps a dozen Erythrina 

 monosperma (Wiliwili). (See Plate XXVII.) The urticaeeous Neraudia Ka- 

 Jioolawensis, the only plant thought to be peculiar to Kahoolawe, was found by 

 the writer on the lava fields of Auahi on the southern slopes of Mt. Haleakala, 

 Maui. Most of the land on this island has no soil, all having been blown into the 

 sea by the wind, after it had been robbed of its vegetation by cattle, sheep, and 

 goats, with which the island was overstocked. The result is that there is nothing 

 left but pure hard-pan, several feet thickness of soil having been blown away. 

 Even now on a windy day the island is not visible, as it is enshrouded in a cloud 

 of red dirt which, when the south wind prevails is carried across the isthmus of 

 the Island of Maui, to be deposited on the already fertile sugar cane fields. 



The Island of Niihau is in a similar state, though is not as eroded as Kahoo- 

 lawe. The native vegetation of this small island has, however, disappeared. 

 Acacia farnesiana and Prosopis juliflora (Kiawe or Algaroba) have been planted 

 on the lowlands. 



In this rather lengthy introduction, the writer has tried to give a more or 

 less detailed description of the various interesting botanical regions of this island 

 group. The present paper by no means claims to be the result of an ecological 

 study, but a mere foundation for such work, which undoubtedly will have to 

 follow. The whole of the introduction is devoted to the floral aspects of this in- 

 teresting island group, and is merely floristic work with here and there an at- 

 tempt to explain some of the ecological features. 



The writer has had occasion, as Botanist of the Board of Agriculture and 

 Forestry and of the College of Hawaii, to visit all the islands of the group, each 

 several times at the various seasons during five years, making a thorough botanical 

 survey of each island, some of the results of which are herewith published. 



Note: — All plants mentioned in this introduction as new to science (trees excluded) are 

 briefly described in the appendix. All new trees mentioned are described in their respective 

 places according to the natural system of classification. 



87 



