^90 Transactions. — Botany. 



" are due to the difficult absorption in peaty soil, the humus 

 acids and the lack of oxygen being detrimental to normal root 

 activities. For similar reasons the normal soil activities of 

 bacteria and fungi are lessened, and, as a result of this 

 relative lack of decay, great quantities of peat accumulate." 



Olearia-Dracopliyllum Bog. 



How far this may be considered a primitive formation I 

 cannot tell, but certainly at the present time the majority of 

 the bogs of the tableland are of this character, and it seems 

 likely that, though all or nearly all of these have been burnt 

 more than once, they have reproduced themselves in large 

 measure as they originally were. On examining such an area 

 after fire it looks at first as if 0. semidentata was going in 

 large measure to replace D. paludosum ; but this appearance 

 is more apparent than real, and depends on the more rapid 

 growth of Olearia, and upon its greater distinctness of aspect, 

 owing to its whitish leaves. 



The soil of this formation is not quite so boggy as that of 

 the Lepyrodia bog, therefore there must be slightly better 

 drainage. All the same, the ground is extremely wet ; water 

 can be always wrung out of the soil, while after a shower of 

 rain the small holes made by the hoofs of cattle and horses 

 remain full of water for many hours. 



Probably this formation originally contained a good deal of 

 Phormium tenax, but that plant at present, as will be seen 

 later on, is almost altogether absent. The undergrowth is 

 much the same as in the Lepyrodia formation. The relative 

 proportion of Dracophyllum and Olearia depends entirely upon 

 the water-content of the soil — the wetter the bog the more 

 plentiful the Olearia. Finally, when the ground becomes a 

 little drier still, the Olearia- Dracophyllum bog merges into the 

 next formation to be described, the Phormium bog, or, if the 

 ground be still more dry, into the Dracophyllum pahulosum 

 formation, a transition between bog and forest. 



'O 



Phormium Bog. 

 This formation, so I learnt from Mr. W. Jacobs, and could 

 also see from its scattered remains, was at one time one of the 

 most important bog formations of the tableland, while P. tenax 

 also, in other parts of the island, was, according to Mr. A. 

 Shand, very abundant in bogs, swamps, and even on the drier 

 ground. At the present time a piece of primeval .Phormium 

 bog is almost unknown, even on the tableland. On a semi- 

 dry ridge near Lake Eangatapu still remains a very small 

 piece of Phormium bog, while all around are the blackened 

 remains of burnt plants. Here Phormium tenax is easily the 

 leading plant. Mixed with it in large quantities is Olearia 



