THE ALPINE FLORA I 3 



drainage another almost invariably neglected, top-dress- 

 ing. Many are too apt to fancy that the benefit of good 

 drainage is summed up in the prevention of stagnant 

 water about the roots. But drainage does far more ; in 

 light soil, where it should especially be deep, it guards 

 against drought as much as in retentive soil against 

 sourness ; by giving free passage to the rain it opens 

 aerating channels and carries warmth through the sub- 

 soil ; it prevents a caking of the surface in fiery sunshine 

 and by checking evaporation prevents an accumulation 

 there of saline constituents and so secures an even distri- 

 bution of inorganic manure throughout the whole feeding 

 ground. And it is upon this slowly dissolving inorganic 

 matter than an alpine chiefly lives. Not but what even 

 in the highest zone there are exstinct lake beds and such 

 like places where alluvial soil has gathered to great 

 depths; there are half drained bogs, so that among our 

 alpines are found plants happy in loam, or peat, or 

 swamp. But the majority are growing in a shallow layer 

 of soil hard upon the native rock. Some may be 

 shallow rooters ; but even these draw most of their 

 sustenance, not from the scanty organic substance around 

 them or from such little portion of the direct rainfall 

 which that layer can retain, but from the ever trickling 

 film of moisture along the surface of the rock, a moisture 

 that fell as rain upon the higher slopes and is now 

 descending charged with soluble inorganic salts; others 

 bury their main roots far down in imperceptible, incon- 

 ceivably narrow fissures, into whose depths little organic 

 matter can penetrate. We could not imitate these 

 fissures except by splitting some huge rock by chisel or 

 wedge and fitting the two edges close together and 



