The number of plants capable of withstanding the prolonged and terrible Arctic winters, and of contenting themselves with the scanty heat and light which the pale sun of those regions pours upon them during his brief stay above the horizon, is, in effect, very limited. We have seen, in the preceding chapter, how restricted is the flora of that part of the American polar lands which has received the somewhat ambitious appellation of the "Wooded Region." This flora, so poor and stunted, is nevertheless the flora of a comparatively fortunate zone. We find it, with some variations, to the north of Sweden, Russia, and Siberia. There we encounter those ultimate masses of foliage which have any pretensions to the title of Forests--Pines, Firs, Elms, and Birches are the only species which compose them. Further north these trees form but small woods, alternating with clumps of poplars and dwarf willows. The Myrtle of our sub-Alpine forests, and a small winding Honeysuckle, with rounded leaves, rosy and fragrant flowers, cover in certain places considerable surfaces. Still further north the arborescent species are completely wanting; but vivacious plants, belonging to the families of Ranunculaceæ, Saxifragaceæ, Cruciferæ, and Gramineæ, spread out their flowers on the surface of the rocks. To the firs and birches, already so stinted, succeed, in the same localities, a few scattered shrubs; among others, the thorny Gooseberry bush, the common Strawberry, the Raspberry-pseudo-Mulberry (_Rubus Chamæmorus_)--exclusively indigenous to these regions--and the Oleander of Lapland (_Rhododendron Laponicum_). Still advancing northward, we meet, on the extreme confines of the continent, some Dravas (_Cruciferæ_), Potentillas (_Rosaceæ_), Bur-weeds and Rushes (_Cyperaceæ_), and, finally, a few Mosses and Lichens. The commonest mosses are the _Splechnum_, which resemble small umbels; and, in moist localities, the _Sphagnum_, or _Bog-Moss_, whose successive accumulation, from a very remote epoch, has formed, with the detritus of some _Cyperaceæ_, extensive breadths of peat, which might be utilized as a combustible. The lichens and the mosses are the last plants which, owing to the simplicity of their organization, are able to develop and reproduce themselves on the Arctic rocks and under the dense layer of snow which covers them. Their abundance in almost all the polar wastes, where every other nutritious plant is wanting, proves an inestimable benefit for the few inhabitants of those deserts. It will suffice to mention, as representatives of the singular family of Cryptogams, the Iceland Moss, which medical science employs in the treatment of pulmonary diseases; and the Reindeer Moss, whose foliaceous expansions frequently cover vast extents of soil, and form veritable pasture-grounds where the reindeer find almost their only nutriment.