322 Transactiois. — Botany. 



After exploring the three peaks overlookmg Alexandra, a start was made 

 to reach the highest peak by proceeding along the crest of the cu'cuitous 

 ridge separating the crater-like chasms before-mentioned ; but the vegeta- 

 tion proved so excessively dense and difficult to penetrate, that after spend- 

 ing the greater part of a day in advancing a distance certainly not exceeding 

 a mile, the attempt was abandoned. Trees dwarfed to the height of a few 

 feet occupied the whole breadth of the ridge, their branches spreading 

 horizontally just above the ground. In some places progress could only be 

 made by creeping on all-fours under the vegetation ; in others even this 

 course could not be followed, and the only means of advance was by walking 

 on the tops of the trees themselves, the branches being so closely interlaced 

 and matted together as to bear the weight of a man for considerable dis- 

 tances. This mode of progression, although allowing the explorer the 

 benefit of a good view in all directions, is not without its disadvantages, 

 as it is not always possible to feel certain of the exact height above the 

 ground he is travelling at, and, on reaching a weak place, he usually 

 descends to terra firma much more suddenly than is at all pleasant or 

 convenient. The dwarfed state of the vegetation is evidently more caused 

 by exposure to the strong winds that periodically sweep over the top of the 

 mountain than to the decreased temperature due to altitude ; for in sheltered 

 places only a few yards below the level of the ridge the same species could 

 be seen growing luxuriantly. In very exposed places it was curious to see 

 comparatively large trees growing out horizontally from the edge of the 

 leeward side of the ridge, their branches cut off level with its surface as 

 regularly as if trimmed with a gardener's shears. The character of the 

 vegetation differed in no respect from that of the peak before described, 

 beuig principally composed of Ixerba hrexioides and Weimnannia raceviosa. 

 The excessive abundance of the former species all over the higher portions 

 of the mountain is a most noteworthy peculiarity. 



Although the flora of Pirongia is certainly a luxuriant one, and might 

 be considered a favourable example of om' forest vegetation, yet it is by no 

 means so numerous in sj)ecies as that of districts situated more to the north. 

 In short, an examination of it clearly bears out the conclusion arrived at 

 by several observers that the ligneous vegetation of New Zealand steadily 

 decreases in the number of species as we proceed southwards. Anyone 

 acquainted with the vegetation of the Cajpe Colville peninsula, or of the hilly 

 district behind Whangarei and the Bay of Islands, or of the range of 

 mountains between Mongonui and Hokianga, and comparing either of them 

 with that of Pirongia, would not fail to recognize this. The number of 

 northern species absent is not counterbalanced by the few southern plants 

 added. 



