DR. HOOKER ON THE DISTRIBUTION OF ARCTIC PLANTS. 
Gl 
Alopecurus alpinus. 
Deyeuxia deschampsioides 
Lapponica. 
Deyeuxia Langsdorffii 
Hierochloe alpina. 
Colpodium latifolium. 
Colpodium pendulinum. 
fulvum. 
Dupontia Fisheri. 
strigosa. 
It is curious to remark how many of these boreal European plants, which are absentees 
in the Alps, have a very wide 
not only extending to the Himalaya and N 
China, but many of them all over Temperate North America ; only one is found in the 
south temperate 
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 glacial 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 different 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 do inhabit the Alps of Europe, 
but not Arctic Europe, is much smaller. Those marked t are Scandinavian, but do not 
enter the arctic circle. 
■ 
Anemone patens. 
alpina. 
narcissiflora. 
fRanunculus sceleratus 
tAconitum Napellus. 
fArabis petrsea. 
fCardamine hirsuta. 
Draba stellata. 
tThlaspi montanum. 
fLepidium ruderale. 
tSagina nodosa. 
tLinum perenne. 
Phaca alpina. 
tAstragalus hypoglottis 
fSpiraea salicifolia. 
fPotentilla fruticosa. 
Potentilla sericea. 
fCeratophyllum deraersum. 
Bupleurum ranunculoides. 
t Viburnum Opulus. 
Galium rubioides. 
Alnus viridis. 
Pinus cembra. 
fSparganium simplex. 
fTypha latifolia. 
Carex ferruginea. 
t 
saxatile. 
t 
supina. 
stricta. 
pilulifera. 
Ptarmica alpina. 
Aster alpinus. 
Gentiana prostrata. 
Polygonum polymorphum. 
Corispermum hyssopifolium 
fScirpus triqueter. 
Deyeuxia varia. 
Spartina cynosuroides. 
fGlyceria fluitans. 
Hordeum jubatum. 
The following are 
s 
Botanical Districts within the Arctic Circle. 
the prominent features, botanical, geographical, and climatal, of 
zone 
the five districts of the arctic 
1. Arctic Europe. — The majority of its plants are included in the Lapland and Einland 
floras ; and, owing to the temperature of the Gulf Stream, which washes its coasts, Lap- 
land is by far the richest province in the arctic regions. The mean annual temperature 
at the polar circle, where it cuts the coast-line, is about 37°, and the June and September 
tempe ra t ures throughout Lapland are 40 
climate favourable both to flowering and fruiting. Spitzbergen belongs to this flora, as do 
Nova Zembla and the arctic countries west of the river Obi, which forms its eastern boun- 
dary ; for the Ural Mountains do not limit the vegetation, any more than do the Rocky 
Mountains in America. Gmelin observed more than a century ago that the river Obi in 
lower latitudes indicates the transition longitude from the European to the Asiatic flora. 
2k2 
and 37° respectively; thus rendering the 
