Cockayne. — Plants of Chatham Island. 261 



the semi-rosettes of leaves can receive the incident light to the 

 best advantage. Below, the stems are marked faintly with the 

 old leaf-scars, thus defining those portions of the plant which 

 have formerly been terminal. It is probable that the oldest 

 portions of the plant — i.e., the most deeply buried portions — 

 die, while the plant continues to increase by the rooting of its 

 terminal shoots. Such a plant might, then, attain to a very 

 great age, so long as it was able to hold its own against ad- 

 vancing sand or denuding wind. The Pimelea mounds are 

 from Ira. to 1*2 m. in height. Sometimes the Pimelea grows 

 unmixed with other vegetation, but more often its protection 

 is taken advantage of by other plants, especially by Deyeuxia 

 billardieri, Isole.pis nodosa, and Accena novce-zela"dim. Such a 

 plant of Pimelea arenaria as described above averages about 

 4 m. in length. 3 m. in breadth, and 47 cm. in height. Another 

 abundant plant of this zone is Gar ex ptcmila, which here 

 grows in association with Convolvulus soldanella. This Carex 

 has also the power of growing upwards as the sand covers it, 

 and, with its stout, long, creeping rhizomes, assists the dune 

 very materially in resisting the wind and the advancing sand. 

 Ranunculus acaulis is also abundant here, playing its part as 

 a sand-binder, and in habit much the same as described before 

 when treating of the strand vegetation. Less abundant than 

 any of the foregoing is Euphorbia glauca, which forms small 

 colonies extending sometimes into the more open parts of the 

 adjacent forest. Its seedlings are fairly plentiful on the sand 

 near the parent plants. Although not very abundant on that 

 part of the dunes here treated of, Scirpus f rondo sits is by far 

 the most characteristic sand-dune plant of the island, and, 

 indeed, of the whole New Zealand area. It can form settle- 

 ments and hold its own in positions where no other New Zea- 

 land flowering-plant can exist, and only the most constant 

 and furious winds can destroy a dune where it is properly 

 established. Indeed, for sand-binding power it is probably 

 not equalled either by Ammophila arenaria or by Elymus 

 arenarius. 



The sand-dunes bearing the forest zone are higher than 

 those just described, and extend inland for a distance of 

 300 m., more or less. The plant-covering consists near the 

 sea entirely of Olearia traversii and Myrsine chathamica ; 

 further inland other trees put in an appearance. 0. tra- 

 versii always maintains its character as a low tree, but 

 M . chathamica loses altogether its tree-like habit as it nears 

 high-water mark, and under the influence of the numerous 

 and sometimes violent sea-breezes becomes a leafy shrub 

 with dense close branches. The difference in appearance 

 between the two forms of this plant is so great that one 

 might very easily mistake them for two distinct plants. 



