46 Transactions. 



Art. XIII. — Notes of a Botanical Visit to Holly ford Valley and Martin's 

 Bay, with a List of Indigenous Plants. 



By D. L. Poppelwbll and W. A. Thomson. 



[Read before the Ota go Institute, 12th June, 1917 ; received by Editors, 22nd December, 



1017 : issued separately, 24th May. 1918.] 



During the Christmas holidays of 1916-17 we, in company with some 

 others, paid a visit to Martin's Bay, via the Hollvford Valley. We spent 

 in all about ten days in the locality, examining the vegetation. Owing to 

 lack of time and the difficult nature of the country, we were unable to 

 climb any of the mountains, and consequently our notes relate only to the 

 forest vegetation of Hollvford Valley and that of Martin's Bay itself. No 

 list of the plants of these areas seems to have yet been published, so we 

 append particulars of those seen by us, with some notes as to the ecological 

 conditions and the forest vegetation. 



Topography and Climate. 



The Hollvford Valley from the point at which we entered it to the sea at 

 Martin's Bay is about forty miles long. For over twenty miles of this 

 distance it runs almost due north, and is bounded on the west by the Darran 

 Range, which consists of very high and precipitous mountains, varying 

 from 7,000 ft. to 9,000 ft. The principal peaks are Mount Christina (8,675 ft.) 

 and Mount Tutoko (9,042 ft.). On the east side the mountains range from 

 4,000 ft. to 6,000 ft. in height. The valley is a narrow one, varying from less 

 than a quarter of a mile to about two miles in width. The lower part trends 

 more to the west, and consists of Lake McKerrow, twelve miles long, and 

 a strip of three miles of level land to the sea. The mountains become much 

 lower as the sea is approached. There is little doubt that this valley is 

 subject to a very large rainfall, as is most of the western side of the South 

 Island. The river is increased during its course by many snow-fed streams, 

 which in the spring must be raging torrents. The Pyke River, which 

 drains Lake Alabaster, is the largest of these streams, and is sufficiently 

 deep to require horses to swim even when quite low, as it was at the time 

 of our visit. We do not think this valley is subject to much frost in winter, 

 and can vouch for the fact of great heat in summer. Our party did not 

 experience a single shower during its visit, and from observations taken 

 with the thermometer the shade temperature for several days exceeded 

 80° F. Where the track meets the valley below Howden Saddle the height 

 above sea-level is between 500 ft. and 600 ft. The fall of the Hollyford 

 River will therefore average about 15 ft. to the mile, although it is much 

 greater in the upper part, as the last fifteen miles (including Lake McKerrow) 

 is tidal. 



Ecological Conditions. 



The narrow valley, hemmed in by high mountains, and the high rainfall 

 make the atmosphere warm and humid, and it consequently affords ideal 

 conditions for plant-life. The soil mostly consists of detritus from the 

 mountains, mixed with decaying vegetable matter, and is therefore rich 

 and suitable for rank and rapid growth. The hanging mosses on all the 

 tree-trunks and branches attest the high degree of atmospheric moisture. 



