Cockayne. — Plants of Chatham Island. 309 



people the ground ; but this is certainly not an example of 

 one plant exterminating and so replacing another. As an 

 example of the power of Phormium growing in ordinary soil 

 to resist aggression, a plant in my garden has grown luxuri- 

 antly for nine years in ground which is a complete mat of the 

 rhizomes of Triticum repens, almost the most aggressive 

 introduced garden weed with which I am acquainted. 



To give an exact account of the changes which come 

 about in a plant-formation after repeated burnings would 

 require close observation extending over a considerable period 

 of time. All that my limited stay on Chatham Island per- 

 mitted was the examination in a number of places of vegeta- 

 tion reproduced after fire growing by the side of portions of 

 original vegetation, or of a vegetation burned at an earlier 

 date, as the case might be. The following are extracts from 

 my notes oil this matter : — 



(a.) " Clear" in Forest at South-west of Island; burned 

 about fifteen months. — Such an open spot as this is probably 

 the remains of a bog once much more extensive, but which is 

 now nearly all replaced by forest. Everywhere the blackened 

 stumps and burnt shrubs are standing, while in the wettest 

 ground the burnt Sphagnum forms large round hummocks. 

 The original vegetation was Olearia semidentata, Lepyrodia 

 traversii, and Dracophyllum paludosum, with the characteristic 

 undergrowth of this particular plant-formation. In the driest 

 places are Lomaria procera, Lepyrodia traversii 15 cm. tall 

 from old rhizome, and also seedlings 3 cm. tall, seedlings 

 of 0. semidentata 8 cm. tall, and D. paludosum seedlings 1cm. 

 tall. In the moister places towards the centre of the 

 "clear" are Carex sp., often forming large green masses, 

 Gleichenia circinata, Lepyrodia travt-rsii, Drosera binata, and 

 seedlings of the Dracophyllum and Olearia as before. The 

 Dracophyllum seedlings are so close together as to touch 

 one another. In 20 cm. by 20 cm. of ground are twenty 

 Carex sp. + one hundred D. paludosum -f- nine 0. semi- 

 dentata + forty stems of L. traversii -\- one Gleichenia cir- 

 aiiitta, but the Olearia, being much larger than the Draco- 

 phyllum, is more conspicuous in the formation generally. 

 From the above it seems that in this case a formation closely 

 akin to the Lepyrodia formation will replace the original pure 

 Sphagnum formation, while in other parts perhaps there will 

 be little change. 



(b.) Boggy Ground near Lake Te Kua Taupo ; vegetation 

 burnt three years ago. — From the remains of the burnt vege- 

 tation still standing it can be seen to have originally consisted 

 of Olearia semidentata 1-8 m. tall, and Dracophyllum palu- 

 dosum perhaps hardly so tall, and probably with the under- 

 growth common to such a combination. The reproduced 



