Herriott. — Plants from the Southern Islands. 381 



ern Islands — cloudy skies, frequent showers, a mild temperature 

 in winter but a cool summer, and, finally, furious gales and 

 squalls with hail or sleet, of which winds the nature of the arbor- 

 escent plants bears abundant evidence " (p. 285). 



On the Bounty Islands there is no vegetation except " an 

 alga clothing the rocks and giving them a greenish hue in places, 

 and on the rocks a mass of a peculiar species of Durvillcea " 

 (p. 297). The prevailing conditions of climate are therefore well 

 summed up in the above description of the climate of Antipodes 

 Island. 



The temperature is pretty uniform throughout the entire 

 year, and active growth is possible for the greater portion of 

 the year. There is very little sunshine, the sky being usually 

 cloudy, and when there is no actual rain the atmosphere will 

 contain considerable moisture. All the islands are subject to 

 rather severe gales, and this has an effect on the number and 

 appearance of the ligneous plants present. On Snares Island 

 and Auckland Islands there is a pretty extensive forest forma- 

 tion, but on Campbell Island, in consequence of severer winds, 

 it is merely a scrub formation ; on Antipodes Islands the scrub 

 is even less developed, while on Macquarie Island there is none 

 at all. 



2. Soil. — The second important factor which influences the 

 form and structure of plants is the nature of the soil in which 

 they grow ; and we find the different soils characterized by dif- 

 ferent formations or associations of plants in which some one 

 plant or more predominates and gives its especial character to 

 the ' formation. Here, again, following Dr. Cockayne's classifi- 

 cation, we get the following formations : (1) Sand-dunes, only 

 on Auckland Island ; (2) coastal rocks ; (3) forest in Auck- 

 land Islands and Snares, scrub in Campbell and Antipodes ; 

 (4) lowland tussock ; (5) meadow formations ; (6) bog in An- 

 tipodes Islands ; (7) subalpine — (a) meadow, (b) rocks. 



Full details of these formations are to be found in Dr. Cock- 

 ayne's paper of 1903 (p. 226). 



The soil in which these plants of the Southern Islands find 

 themselves situated is therefore generally of a moist peaty 

 nature, and not one which at first sight calls for modifications 

 to check the amount of water transpired ; but an examination 

 of the chemical composition of such a soil shows that it must 

 necessarily consist of various salts, which the water to be taken 

 into the roots will dissolve. In swampy districts, also, there 

 is a great percentage of humic acid present, and this is harm- 

 ful when taken into the tissues of the plants. In the first 

 case, " salts that are dissolved by the water in the soil influ- 

 ence the osmotic processes, and consequently the absorption of 



