322 Transactions.— Botany. 
After exploring the three peaks overlooking Alexandra, a start was made 
to reach the highest peak by proceeding along the crest of the circuitous 
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, 
being principally composed of Ixerba brexioides and Weinmannia racemosa. 
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 our forest vegetation, yet it is by no 
means so numerous in species 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 Cape 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. 
