256 Transactions. — Botany. 



unmodified. From a careful study of the present plant- 

 covering in a large number of places it seems certainly 

 possible in many instances to get a fairly accurate idea of 

 the original formations, especially when aided by the in- 

 formation of those who have resided on the island almost 

 from its first settlement by Europeans. Those small pieces 

 of original vegetation which from their peculiar situation 

 have up to the present been undisturbed also aid most 

 notably in affording a clue to the character of similar forma- 

 tions in other parts of the island ; but, of course, the results 

 deduced from such a comparison must be accepted with 

 caution, since a slight difference in edaphic conditions may 

 lead to more or less considerable changes in a formation. 

 In some instances the descriptions of the individual plant- 

 formations which follow are limited to certain stated locali- 

 ties. 



Dr. H. C. Cowles very justly observes (14 2 , p. 178) that 

 "plant societies must be grouped according to origins and 

 relationships, and the idea of constant change must be 

 strongly emphasized"; and, further, "The laws that govern 

 changes are mainly physiographic ; whether we have broad 

 flood plains, xerophytic hills, or undrained swamps depends 

 on the past and present of the ever-changing topography." 

 The above ideas I have attempted to in some small degree 

 carry out, and have taken for the most part the plant-forma- 

 tions in what seems to me their order of sequence, and have 

 sought in some instances to point out their relationships. 

 To have attempted, however, a physiographical classification 

 of the formations with any degree of thoroughness was out 

 of tne question. Such would require, in the first place, to be 

 based on what does not yet exist — a description of the topo- 

 graphical geology of the island by a competent geologist ; 

 and, in the second place, a very much more accurate study 

 of the formations than I was able to make would be essential. 



There are on Chatham Island two distinct regions of 

 vegetation, of which the most marked difference is shown 

 by the forests. The one is confined to the tableland, and 

 the other comprises all the remainder of the island. For 

 this latter I suggest the name "lowland region," a not par- 

 ticularly good name, but sufficiently applicable, since most 

 of its surface is only a few metres above sea-level, while its 

 hills are low isolated volcanic cones. Probably some of the 

 differences between the vegetation of the tableland and low- 

 land regions have been accentuated by fires, &c, while the 

 woods above the north-west and west coast of the southern 

 part of the island seem, so far as a rapid examination showed, 

 to be in some degree a transition between lowland and 

 tableland forest. All the same, the differences between the 



