Cockayne. — Plants of Chatham Island. 291 



semidentata and Dracophyllum paludosum, the whole growing 

 quite as closely as do the plants in the Lepyrodia bog. My 

 notes give no list of the undergrowth ; possibly in so dense a 

 mass there could not be much. 



Phormium, before it was eradicated, grew in especial pro- 

 fusion on the banks of the tableland streams, where the 

 drainage would be better and the humus acids of the soil less 

 than in the more stagnant parts of the bog. Such a stream 

 may have the water visible in the centre of the channel, the 

 rest of its bed being full of Sphagnum, while growing just 

 in the water and on both sides of the creek are Phormium 

 tenax, Carex secta, Hierochloe redolens, the whole mixed 

 with Dracophyllum paludosum and Olearia semidentata. 

 Growing on the Sphagnum is Cotula asiatica, Isolepis sp., 

 Poa chathamica, and Juncus planifolius. 



Phormium tenax of the Chatham Islands differs from the 

 f orms usually seen in New Zealand in that its leaves are not 

 so stiff, are broader, and usually droop considerably at their 

 extremities. 



Dracophyllum paludosum Formation. 



This formation seems to be a distinct transition between 

 bog and forest. It is usually found adjacent to the forest, 

 and consequently on the summit of a ridge, for the forest 

 occupies the sides of gullies. The dominant plant is Draco- 

 phyllum pahidosum, mixed with which are here and there 

 small trees of D. arborcum; or juvenile plants of this latter 

 nearly as tall as the D. paludosum may be abundant, and 

 which still possess only their broad leaves. The D. pahi- 

 dosum is about 1*6 m. tall, and the shrubs so close to- 

 gether that one has to force them apart in walking through 

 the formation. On the ground grows Poa chathamica, Gen- 

 tiana umbellata, Pratia arenaria, Pteris esculenta (occasion- 

 ally), and a few seedlings of both forms of Dracophyllum. 

 Not unusually seedlings of other of the forest trees are 

 present, and there is no reason why, when they attain a 

 larger size, they should not destroy the adjacent D. palu- 

 dosum. Here and there are also a few full-sized plants 

 of Olearia semidentata, but in this drier ground that plant 

 cannot compete with the Dracophyllum. The part most 

 adjacent to the forest contains the greater number of D. 

 arboreum, and that zone may be considered the line of tension 

 between forest and bog. 



The Tableland Forest. 



Greater moisture and a more peaty soil with a great 

 capacity for holding water seem to be the chief cecological 

 factors which have separated this formation from the lowland 



