208 HOOKER ON ARCTIC PLANTS. 



perate zone of Asia, and very few of them in Temperate South 

 Africa. 



There are, however, a considerable nmnber of Scandinavian 

 plants which are not fomid in the Alps of Middle Europe, though 

 found in the Caucasus, Himalaya, &c., and conversely there are 

 several Arctic-Asiatic and -American plants found in the Alps of 

 Central Europe, but nowhere in Arctic Europe. In other words, 

 certain species extend from Arctic America westward to Arctic 

 Europe, and there are certain other species which extend from 

 Arctic Europe to the Caucasus and Central Asia, which neither 

 exist on the Alps of Central Europe nor extend eastward to 

 Arctic America : — 



[Here follows a list of 103 species of plants common to Arctic 

 Europe and Temperate Asia, &c., but not to the Alps of Europe, 

 pp. 260-1.] 



It is curious to remark how many of these Boreal European 

 plants, which are absentees in the Alps, have a very wide range, 

 not only extending to the Himalaya and North China, but many 

 of them all over Temperate North China ; only one is found in the 

 South-temperate zone. In the present state of our knowledge we 

 cannot account for the absence of these in the Alps ; either they 

 were not natives of Arctic Europe immediately previous to the 

 Grlacial Period, or, if so, and they were then driven south to the 

 Alps, they were afterwards there exterminated ; or, lastly, they 

 still inhabit the Alps under disguised forms, which pass for dif- 

 ferent species. Probably some belong to each of these categories. 

 I need hardly remark that none inhabit Europe south of the Alps, 

 or any part of the African continent. 



The list of Arctic- American and -Asiatic species which inhabit the 

 Alps of Europe, but not Arctic Europe, is much smaller. Those 

 marked "f are Scandinavian, but do not enter the Arctic Circle : — 



Anemone patens. Galium rubioides. 



A. alpina. t Gr. saxatile. 



A. narcissiflora. Ptarmica alpina. 



j" Ranunculus sceleratus. Aster alpinus. 



f Aconitum Napellus. Gentiana prostrata. 



f Arabis petrsea. Polygonum polymorphum. 



f Cardamine hirsuta. Corispermum hyssopifolium. 



Draba stellata. Alnus viridis. 



f Thlaspi montanum. Pinus cembra. 



f Lepidium ruderale. f Sparganium simplex, 



f Sagina nodosa. t Typha latifolia. 



f Linum perenne. Carex ferruginea. 



Phaca alpina. C. supina. 



I Astragalus hypoglottis. C. stricta. 



f Spiraea salicifolia. f C. piluHfera. 



f Potentilla fruticosa. Scirpus triqueter. 



P. sericea. Deyeuxia varia. 



■f Ceratophyllum demersum. Spartina cynosuroidcs. 



Bupleurum ranunculoides. f Glyceria fluitans. 



•f Viburnum Opulus. Hordeum jubatum. 



