A MOUNT WASHINGTON SANDWORT 599 



Arctic Circle to a mere dwarf ; and it is the dwarf form whose leaves 

 occur among the glacial debris of the Norfolk clay-bed. Side by side 

 with it we find the scanty remains of a stunted northern willow 

 (Salix poldris), another of the numerous pygmy shapes which the 

 polymorphous willow type knows so well how to take on under fitting 

 circumstances. It is hard, indeed, to conceive how anybody could ever 

 have watched the gradual stunting of the trees and shrubs, as we 

 ascend a mountain, or approach the Arctic Circle, and yet believe in 

 the separate and deliberate creation of dwarf forms for such great 

 altitudes or high latitudes, like the Mount "Washington willcws or the 

 polar birch. If we trace the gradual degeneracy of the temperate 

 birchen type, represented by the beautiful American silver or paper 

 birches, through your own shrubby Betula purinla of the Northern 

 bogs, and your petty Betula glandulosa of the high mountains, to the 

 insignificant Betula nana of the arctic regions and of glacial times, 

 it is impossible not to recognize in the entire series one long degrada- 

 tion of a primitive form. Similarly in the willows : every intermedi- 

 ate step may easily be identified, from the large and handsome weep- 

 ing-willows, through shrubby forms like Salix Bapponam, Salix refens, 

 and Salix ynyrsinites, till we reach at last the final term in the tiny 

 Salix herbaeea of the White Mountains. All are species degraded 

 from a tall and vigorous ancestral tree by the harsh conditions which 

 prevailed at the coming in of the Glacial Epoch. 



The shrubs, of course, have fared no better than the forest-trees ; 

 but, like the forest-trees themselves, and the lowly herbs, they have 

 learned to accommodate themselves to the situation. Thus the bram- 

 ble kind, after growing down from the high blackberry and the black 

 raspberry to the level of the trailing dewberry (Bubus Canadensis) 

 and the dwarf raspberry (Bubus trifloms), reaches at last an almost 

 herbaceous type in our British Bubus saxatilis, and finally ends in a 

 mere herb, no bigger than a strawberry-vine, in the true cloudberry of 

 the arctic regions and the New Hampshire hills. So, too, the cornels, 

 starting with your glorious flowering dogwood ( Cormis florida), which 

 alone is worth a visit across the Atlantic to see, ends at last in the 

 pretty little bunchberry ( C. Canadensis) that carpets the woodlands 

 of the high North. And so, once more, the heath family, starting 

 from the noble rhododendron and mountain laurels that glorify and 

 brighten your American hills, tails off at last into the low, spreading, 

 and tufted bog-bilberry, confined entirely to Alpine tops on both sides 

 of the water, and to the mountain bearberry, whose low mats cover 

 the interstices of the rocks among the "White Mountains and the 

 higher Maine hills. Everywhere the habit of all these sub-Arctic and 

 glacial plants is just the same, whether their ancestors started in life 

 as trees, or shrubs, or bushes, or herbs ; the Alpine azalea is as low 

 and as tufted as the crowberry that mimics it ; the Labrador tea is as 

 tiny and as inconspicuous as the Greenland sandwort. On all of them 



