Cockay>'E — Plants of Chatham Island. 299 



tableland ridges are covered with this formation, and it seems 

 probable that much of the bracken-covered ridges of other 

 parts of the island was originally of this nature. Whether 

 the formation is almost a primitive one or whether it has 

 become considerably modified I cannot say ; probably at one 

 time it contained a good deal of Phormium tenax. 



The most characteristic plant is Cyathodes robust a. This 

 forms large rounded bushes of considerably greater breadth 

 than height, with the leaves all touching, and forming quite a 

 dense mass. The leaves are 15 mm. long by 3 mm. broad, 

 more or less, stiff, coriaceous, green on upper surface, but with 

 the under-surface marked with parallel ridges separating about 

 nine furrows, which are covered with wax. The drupes are 

 large and very abundant ; on some bushes they are red and 

 on others white, when ripe. The bushes of C. robusta are 

 situated at some distance apart, and growing in the open 

 ground between them are tussocks of Uncmia sp. ; Gentiana 

 pleuroqynoides var. umbellata; Accena novce-zelandice ; Gna- 

 phalium filicaule, forming large round silvery patches after 

 the manner of the Baoulias of New Zealand river-beds ; 

 Lomaria procera ; Hydrocotyle asiatica ; Pteris incisa ; Pteris 

 esculenta ; Lagenophora forsteri ; Luzula sp. ; P ratio, are- 

 naria. 



The ridges on which this formation occurs are much ex- 

 posed to the wind, which may account for the ball-like shape 

 of the Cyathodes. Growing close to the Cyathodes formation 

 on one ridge examined was a small patch of trees of Coprosma 

 chathamica, Myrsine chathamica, and Gorokia macrocarpa ; 

 while at the margins of the formation the vegetation became 

 mixed with Dracophyllum paludosum and D. arboreum. It 

 seems from this that here, as in the bracken formation of the 

 lowland, wind is the factor which decides whether forest shall 

 take final possession of the soil. There are certainly a num- 

 ber of plants in this formation which are not included in my 

 notes, but here, as elsewhere, only those are quoted which 

 were actually written down, and throughout this paper no 

 exhaustive list of plants is anywhere attempted. 



Bock. 



Leaving out of the question the mosses, the lichens, and 

 those other cryptogams which are the first plants to clothe 

 the naked rock, and consequently a most primitive plant-for- 

 mation, the phanerogams and ferns which inhabit unshaded 

 rocks are only such as, aided by special xerophytic adapta- 

 tions, can tolerate a position of such extreme dryness. They 

 usually consist of such plants as can be brought readily by birds 

 or wind. Some of these come doubtless at first as mere casual 

 visitors, but, being able to maintain themselves by various 



