Conifers 



they now extend, for Werchojansk is much colder than 

 many places beyond the range of conifers. This seems 

 remarkable when these pines inhabit a country which 

 is buried in deep snow for months together, but it is 

 nevertheless true that pine needles die of drought even 

 when the ground is everywhere snow-covered. 



Suppose under these conditions that the sun shines 

 out and an icy wind begins to blow, then the snow 

 rapidly melts and the leaves at once begin to try and 

 form sugar. But where is the water to come from ? 

 The roots are buried in ground frozen solid for several 

 feet downwards, and even the sap in the stem is nothing 

 but ice. So it often happens that the needles wither, 

 turn brown, and drop off. This happens even to our 

 own hardy Scotch pine when there is a day or two of 

 brilliant sunshine during a very hard frost. 



It is this danger also that explains some of the most 

 remarkable peculiarities of pine needles. The blue- 

 green, waxy appearance, the solid fleshy sort of structure, 

 and the way in which the breathing pores are sunk 

 below the surface, are all at once understood by re- 

 membering this danger of drought. 



In other respects conifers show that they are well 

 fitted to resist both cold and snow. They store up 

 their winter reserve-stores in the form of fat or oil, not 

 as starch.^ This has been compared to the fattening 

 up of bears and other hibernating animals, and it is at 

 any rate true that the vegetable fatty and oily substances 

 are better fitted to resist the effect of hard frost. The 

 resinous character of most coniferous trees is also of 

 great importance, for wounds caused by a broken branch, 

 or some insect which burrows into the wood, are effec- 

 tively sealed up. Conifers always possess a root-fungus 

 or Mycorhiza, so that they are able, like heather, &c., 

 to use peaty soil in which ordinary plants do not thrive. 

 As we have already seen elsewhere, they follow on after 



237 



