EuTLAND.— r/zc Fall of the Leaf. 113 



under the influence of cold can be well observed amongst our 

 cultivated fuchsias, some of which in this climate merely lose 

 their leaves, while others have their stems wholly or partly 

 cut off. Of several varieties I find Fuchsia fuJgens the most 

 susceptible of cold. It is the first to shed its leaves on the 

 approach of winter, during which the stems are invariably 

 destroyed, even when the plants are kept within the shelter 

 of a verandah; yet a specimen taken from here to the 

 Eocks, before mentioned, retains not only its stems, but a 

 portion of its leaves, and on one occasion I noticed it in flower 

 during the winter months. 



One more effect of cold — the dwarfing-down of vegetable 

 forms — requires mention. This is well illustrated by our 

 Alseuosmia ^nacrophylla, which in the North Island is a 

 bushy shrub 4ft. to 5ft. in height, but here rarely exceeds 1ft., 

 the stem being seldom branched. 



From the foregoing considerations and examples we seem 

 to arrive at the following general conclusions : That, though 

 the majority of existing evergreen plants would at once perish 

 were the temperature of the air and soil in which they grow 

 reduced below a certain point, a few, owing to some structural 

 peculiarity, would shed their leaves or suffer the loss of their 

 stems before they finally succumbed, and that in this latter 

 fact we have the immediate origin of the deciduous tree. 



The effects of cold consequent on the changing seasons 

 and the effects produced by the artificial removal of species 

 from their proper habitat to higher latitudes, come within 

 the scope of observation and experiment ; but we have now 

 to consider a portion of our subject of a more speculative 

 character — namely, the effects of a loioering temperature 

 tlirough climatic changes. 



That various portions of the earth's surface have, during 

 different periods of their history, been subjected to very 

 different climatic conditions is one of the most important facts 

 made known by the researches of geologists. In Europe, 

 where the grape i:iow ripens the reindeer once roamed ; and 

 here, in the Wairau Valley, within a few miles of where I 

 vsnrite, are the moraines of an ancient glacier shown in the 

 Upper and Lower Travers hills, the latter being only about 

 1,000ft. above sea-level. 



The climatic changes which the earth has undergone are 

 plainly referable to two causes. One, alteration in the eleva- 

 tion of the land, converting low land into alpine climates, is 

 easily understood ; the other, though its operation has been 

 on a much more extensive scale, remains, as far as I am 

 aware, yet undiscovered. I refer to the Glacial Period, that 

 followed after the deposition of the tertiary rocks in the 

 northern hemisphere. 



