90 



THE HEATH. 



sure, however, till you have closely inspected the 

 rock, that the surface is bare; for it would be 

 scarcely less strange that the flint-stone should 

 have its parasites than the interior of a grain of 

 wheat. And in fact, rugged and hard as the face 

 of the rock appears, and indeed is, you will scarcely 

 be able to touch a spot where there is not, between 

 the substance of the rock and your hand, a living 

 and flourishing vegetable. Yes, even on the 

 polished surface of flints, plants will grow and 

 spread. I do not say that their roots will pene- 

 trate the rock, but perfect plants will spring up, 

 and ripen their seeds where there is not the 

 minutest particle of earth. Examine the face of 

 this mass of granite, which is composed of crystals 

 of feltspar and quartz (two substances hard 

 enough to scratch glass), with a few scales of mica 

 scattered here and there. On one part of its sur- 

 face you will observe a number of irregularly 

 arranged oblong black spots,* which are dry, and 

 so hard as to be in all appearance a part of the 

 stem itself. In reality they are organized living 

 bodies, which have sprung from seed lodged here 

 by the wind, and contain within them the embryo 

 of numerous other plants, in fact, like the poppy- 

 head or bean-pod, mature seed-vessels. Adjoining 

 these, is an irregularly shaped patch of greenish 

 yellow substance which you will in vain attempt to 

 remove with your knife.f Beautifully traversed 

 as it is with meandering veins, and dark spots 

 resembling the rivers and towns in a map, it is so 

 thin, that you will find it impossible to secure a 

 specimen, unless you can detach a portion of the 

 rock to which it adheres. Close by it grows (for 

 * Opegrapha saxatilis. t Leeidea geographica. 



