Cockayne. — Plants of Chatham Island. 2(59 



indeed, the whole formation, especially as seen at Te Wha- 

 karu, must have been enormously modified. 



Limestone Cliffs and Bocks. 



These cliffs bound the shore of the great lagoon in various 

 places, while often rocks extend from their base into the 

 water. At one time the base of the cliffs was laved by the 

 waters of the ocean, so that they are closely related to 

 maritime cliffs. From such cliffs, as before described, they 

 differ in their inland position and consequent freedom from 

 the influence of salt water, also in the very different nature 

 ot the rock. Many of their plant inhabitants are doubtless 

 part of the original flora, while others have come from the 

 neighbouring inland formations, their seeds blown into cre- 

 vices of the rocks or brought by birds, while the xerophytic 

 structure of the plants has enabled them to hold their own 

 in such a position. 



Taking the case of New Zealand, it seems well established 

 that sea-coast plants can continue to occupy an inland ancient 

 maritime station. Mr. T. Kirk has called attention to such 

 an instance (42 2 ), and I have also shown that Angelica geni- 

 culate/, occurs at the lower Waimakariri Gorge, on the upper 

 Canterbury Plains (10 2 , p. 101), a station which Captain Hut- 

 ton brings good evidence to show was formerly maritime (33 2 ; . 



As in all rock-formations, there is here no struggle for 

 existence amongst the plants. Any plant which can gain a 

 foothold will be unmolested by its neighbours. Many parts of 

 the cliffs are quite bare ; others are clothed with a fairly 

 abundant vegetation. Very characteristic of this formation is 

 Veronica dieffenbachii, the branches of which spread out 

 laterally or hang downwards from a thick main stem firmly 

 embedded in some crevice. Its leaves are confined to the ex- 

 tremities of the branches. They are rather thick and fleshy, 

 6-5 cm. long by 1-9 cm. broad. The shoots, unlike those of 

 V. chathamica, are not at all dorsi-ventral, and the branches 

 are so extremely pliant that a twig 4 mm. in diameter can be 

 rolled round and round the finger without breaking. Other 

 plants growdng in company with V. dieffenbachii are — Linum 

 mottogynum var. chathamicum, its white flowers striped or 

 flaked with pale-blue ; Senccio latitus ; Phormnim tenax ; 

 Leucopogon richei ; Accena novee,-zeiandice. In hollows in the 

 cliff Adiantum affine is very abundant, while in some places its 

 delicate fronds form great sheets of greenery on the rocks. 

 Geranium traversii, another common plant of this formation, 

 can thrive in extremely dry positions ; for example, I noted it 

 growing on a perfectly dry limestone rock pear the margin of 

 the lagoon. Its roots are very thick and stout ; one example 

 measured was 1-5. cm. in diameter, and at 10 cm. from the 



