90 HOUSE, GARDEN, AND FIELD 



the tables of Hooker's memoir justify the following very 

 different propositions : 



(1) There is no extensive and characteristic arctic flora. 

 There is indeed a scanty assemblage of peculiar arctic 

 species, but most arctic plants, especially such as are wide- 

 spread and frequent, are, like the purple saxifrage, found 

 also in temperate Europe, temperate Asia, or temperate 

 North America. 



(2) There is an extensive and characteristic European 

 alpine flora, which comprises so many peculiar species that 

 it is probably much older than the Glacial Period. 



(3) The arctic and alpine floras are by no means 

 identical. Such characteristic alpine genera as Gentiana, 

 Primula and Soldanella hardly occur within the arctic 

 circle. Though the so-called arctic flora has many species 

 in common with the alpine flora, these common species 

 are in by far the greater number of cases characteristic 

 of neither ; they are generally frequent and wide-spread in 

 the interjacent lands at all elevations. Among these may 

 be named the buttercups (several species), lady's smock, 

 shepherd's purse, dog-violet, campion, wood-sorrel, the 

 commonest clovers and vetches, silver-weed, coltsfoot, 

 milfoil, dandelion, harebell, ling, thyme, speedwell, the 

 plantains, sorrel, crowberry, and the nettles, besides most 

 of the rushes, sedges and grasses. The reputed arctic- 

 alpine species are often far more plentiful outside the 

 arctic and alpine regions than within them. 



(4) The arctic-alpine species are by no means restricted 

 in temperate countries to heights, but often thrive at 

 moderate elevations, if not pressed too hard by man or by 

 competing species. 



Cold, wind, and other severe climatic conditions have 

 brought about in not a few plants special adaptations to 

 arctic and alpine conditions. The experiments of Bonnier 

 show how directly and rapidly transplantation from small 

 to great elevations may act upon certain plants, inducing 

 reduction in size of parts exposed to air, crowding of leaves 



