Chap, ii.] ZONAL DISTRIBUTION OF PLANTS. 39 



went however, and did not suffer, and I cannot help thinking 

 that it is to some extent the extremely rare occurrence of rain 

 which inspires dread of it in St. Vincent. Our party of three 

 started on two ponies and a donkey, over the latter of which 

 Murray soon broke a pet walking-stick of mine of Bermuda 

 juniper, in trying to urge him into the right path. A strapping 

 negress, one of the coaling gang, started on foot for the moun- 

 tain with the lunch on her head. 



The road led over the bottom of the old crater, and then up 

 the steeper end of the mountain by a zigzag path in places 

 built up in steps and in others hewn out of the rock. The soft 

 friable soil of the plain was in many places already converted 

 into tenacious mud by the rain. 



As the hill-slopes are ascended from the plains, the plants 

 become greener and more abundant. In a narrow gorge at 

 the commencement of the ascent of the mountain, some small 

 gardens were passed, at an elevation of about 200 feet above 

 sea level. They contained sugar-cane, pumpkins, and a small 

 date palm ; and maize was just being planted in them. There 

 were a few cotton bushes growing near. At 700 feet. Euphor- 

 bias and woody Composites commenced, and the hill-side was 

 covered with coarse dry grass. At r,ooo feet, small Boragi- 

 naceoiis bushes with pink flowers {Echhim sfenosiphon) com- 

 menced. At 1,300 feet I found the first patch of moss and 

 Marcha7itia, with a fern and a live snail. At 1,700 feet a 

 Statice (6". Jovis barba) was abundant on the cliff. 



The lavender grows right up to the top of the mountain, but 

 is there entirely fresh and green instead of black and withered 

 as below. A leafless trailing Asclepiad {Sarcostemma Da/totii) 

 commenced at 900 feet. All the plants on Green Mountain 

 appear to extend their range of growth to the summit. On 

 the summit, the land is all more or less under cultivation, and 

 maize, potatoes, tomatoes, and pumpkins grow there. There 

 are several cottages on the summit, and near one is a double 

 circle of large Agaves. 



In the Green Mountain, the appearance of the several 

 plants at successive heights is due mainly to the gradual 

 increase in amount of moisture received by the soil as a higher 

 and higher zone is reached. Closely similar conditions deter- 

 mine the distribution of plants on many other mountains, such 

 as on Green Mountain in the Island of Ascension. 



The distribution of plants in successive zones on mountains 

 which is most familiar, is that brought about by a successive 

 decrease in temperature with increase of altitude, the Alpine 

 flora being that which withstands a prolonged covering of snow. 

 In Kerguelen's Land thus, a rapid decrease of vegetation is 



