266 Plant Life and Evolution 



and probably in time will extend itself to meet the 

 forest belt near the shore. 



Professor Ernst, who accompanied the party in 

 1906, has since published a full account of the flora 

 as it was noted at the time of this visit. (" The 

 New Flora of Krakatau," by A. Ernst : Cambridge 

 University Press, 1909.) 



THE AGENTS IN PLANT DISTRIBUTION 



Man as an Agent in Plant Distribution. The 

 agents in plant distribution are many. Wind and 

 water may be the vehicles of transportation, and 

 many animals, especially birds, are often the agents 

 of rapid dissemination of many seeds and fruits 

 which are often provided with special organs facili- 

 tating their distribution. With the rapid spread of 

 man into the remoter parts of the earth, many plants 

 have been carried with him, intentionally or other- 

 wise, and these have often very quickly made them- 

 selves at home, and sometimes have driven out their 

 native competitors, very much as the white man has 

 driven out the less fit savage. The rapid spread of 

 these imported plants often gives quite a different 

 aspect to the region which they have invaded from 

 what it had before, and may disguise the essential 

 differences which existed between it and other re- 

 gions. It is often very hard to trace the origin of 

 some of these imported plants, and the task of the 

 student of plant geography is greatly increased by 



