Soil-Makers 25 



cling fast even to the bare rock. Once settled, they begin 

 to grow, and are the first traces of vegetable life to make 

 their appearance upon recent streams of lava. They may 

 truly be called "traces," for the first-comers are nothing 

 more than helpless looking stains, or dust, hardly notice- 

 able except by those on the lookout for them; and one 

 would have said anything but dangerous to the rock, 

 for they look not only perfectly inactive, but entirely 

 hfeless. 



The lava has resisted for some time. For years it did 

 not even cool, and it has scorched innumerable lichen 

 spores to death in their attempt to settle upon it. Even 

 when the surface had cooled there was for a long time 

 heat enough within to dry all the life out of them; while 

 multitudes have found the glossy surface too glossy even 

 for their powers of clinging, and have been blown away 

 as fast as they came. There are some streams of lava 

 which are as glossy now as when they were first poured 

 forth three or four hundred years ago, and no lichens 

 have as yet- managed to gain a footing there. But they 

 are not generally kept so long at bay. They return to 

 the charge again and again, helped by the pioneers, who 

 have also been at work meantime, and have gradually 

 roughened the surface a little, or at least have taken off 

 some of the glossiness; and at last the spores manage to 

 settle and fix themselves so firmly that neither wind nor 

 rain can dislodge them, and they begin to grow and spread 

 at their ease. 



Then, in spite of what was said in the previous chap- 

 ter, these vegetables, at all events, must live on air and 

 water? 



Not at all! Lichens are very substantial feeders 



