Notes on the Naturalized Flora of the 

 Hawaiian Islands. 



By Charles N. Forbes. 



The following plants are mainly species not recorded in 

 Hillebrand's Flora,' the majorit}- of them having probably be- 

 come naturalized since 1886. The only record of the naturalized 

 plants which we have had since that time is an addition of a few 

 species in an article by Heller.^ In order to make these notes 

 complete these species are again mentioned in this paper. It is 

 the intention to continue the notes at irregular intervals as 

 material accumulates. 



The naturalized flora occupies the lower valleys and plains, 

 the number of indigenous plants in these localities at present be- 

 ing insignificant. This flora is rapidly encroaching on the native 

 forest, especially w'here its conditions are changed by fires or 

 grazing. Introduced weeds appear along new trails through the 

 native forest in from two to three weeks in places where it would 

 be impossible to find them before. In the unforested sections of 

 the islands, as a large proportion of the slopes of Haleakala on 

 Maui, naturalized plants occur to the very summit (10,000 feet). 

 A few of the naturalized plants as Crepis japonica are an excep- 

 tion to the rule, in that they occur in the dense forest and are 

 rarely found on the plains ; and perhaps a few of the plants con- 

 sidered as indigenous may belong in this category. 



' W Hillebrand. Flora of the Hawaiian Islands, 1888. 

 *A. A. Heller. Minnesota Botanical Studies, Bulletin Xo. 9, pp. 760-922. 

 A portion of Heller's collections are in the Herbarium of the Bishop Museum. 



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