218 



•HOOKER ON ARCTIC PLANTS. 



portion of genera to species being 1:2. Of these 207 species, 

 the following 1 1 alone are not European :— 



Anemone Richardsonii (Asiatic). 



TiuTitis mollis (Asiatic). 



Vesicaria arctica (American 

 only). 



Drab a aurea (Rocky Mountains 

 and Labrador only). 



Arenaria Groenlandica (Moun- 

 tains of U.S.). 



Potentilla tridentata (Labra- 

 dor only). 



Saxifraga triscuspidata (Labra- 

 dor only). 



Erigeron compositus (American 

 only). 



Pedicularis euphrasioides (Asia), 



On the other hand, no less than 57 Arctic-Greenland species 

 are absent in Arctic East America, and the following 36 Arctic- 

 Europe and Greenland species are either absent in all parts of 

 Eastern Temperate America, or are extremely local there : — 



Arabis alpina (Labrador only). 



Lychnis alpina (Labrador only). 



L. dioica (absent). 



Spergula nivalis (absent). 



Arenaria uliginosa (absent). 



A. ciliata (absent). 



Stellaria cerastioides (absent). 



Alchemilla alpina (absent). 



A. vulgaris (Labrador only). 



Sibbaldia procumbens (United 

 States only). 



Rubus saxatilis (absent). 



Potentilla verna (Labrador 

 only). 



Sedum villosum (absent). 



Saxifraga Cotyledon (Labrador 

 and Rocky Mountains only). 



Galium saxatile (absent). 



Gnaphalium sylvaticum (Labra- 

 dor only). 



G. supinum L. (Labrador and 

 White Mountains only). 



Cassiopeia hypnoides (Labra- 

 dor only). 



Phyllodoce taxifolia (Labrador 

 and White Mountains). 



Gentiana nivalis (Labrador 

 only). 



Thymus serpyllum (absent). 



Veronica alpina (White Moun- 

 tains only). 



V. saxatilis (absent). 



Euphrasia officinalis (N. U. 

 States). 



Bartsia alpina (Labrador only). 



Rumex acetosella (absent). 



Salix Arbuscula (absent). 



Peristylus albidus (absent). 



Carex capitata (White Moun- 

 tains only). 



C. mieroglochin (absent). 



C. microstachya (absent). 



C. pedata (absent). 



Elyna caricina (Rocky Moun- 

 tains only). 



Phleum alpinum (Labrador and 

 White Mountains only). 



Calamagrostis lanceolata (La- 

 brador only). 



Deschampsia alpina (absent). 



When it is considered how extremely common most of these 

 plants are throughout Europe and Northern Asia, and that some 

 of them inhabit also N.W. America, their absence in Eastern 

 America is even more remarkable than their presence in Green- 

 land. 



Another singular feature of both Arctic and Temperate Green- 

 land is its wanting a vast number of Arctic plants which are 

 European, and are found also in America. The following ii a 



