This snow, which after it has once fallen persists until the long summer’s day has effectually thawed it, protects in an admirable manner the vegetation of the higher latitudes against the cold of the long winter season. For snow is so bad a conductor of heat, that in mid-winter in the high latitude of 78° 50° (Rensselaer Bay), while the surface temperature was as low as -30°, Kane found at two feet deep a temperature of -8°, at four feet +2°, and at eight feet +26°, or no more than six degrees below the freezing-point of water. Thus covered by a warm crystal snow-mantle, the northern plants pass the long winter in a comparatively mild temperature, high enough to maintain their life, while, without, icy blasts--capable of converting mercury into a solid body--howl over the naked wilderness; and as the first snow-falls are more cellular and less condensed than the nearly impalpable powder of winter, Kane justly observes that no “eider-down in the cradle of an infant is tucked in more kindly than the sleeping-dress of winter about the feeble plant-life of the Arctic zone.” Thanks to this protection, and to the influence of a sun which for months circles above the horizon, and in favorable localities calls forth the powers of vegetation in an incredibly short time, even Washington, Grinnell Land, and Spitzbergen are able to boast of flowers. Morton plucked a crucifer at Cape Constitution (80° 45’ N. lat.), and, on the banks of Mary Minturn River (78° 52’), Kane came across a flower-growth which, though drearily Arctic in its type, was rich in variety and coloring. Amid festuca and other tufted grasses twinkled the purple lychnis and the white star of the chickweed; and, not without its pleasing associations, he recognized a solitary hesperis--the Arctic representative of the wall-flowers of home. [Illustration: 4. ROCKS AND ICE.] Next to the lichens and mosses, which form the chief vegetation of the treeless zone, the cruciferæ, the grasses, the saxifragas, the caryophyllæ, and the compositæ are the families of plants most largely represented, in the barren grounds or tundri. Though vegetation becomes more and more uniform on advancing to the north, yet the number of individual plants does not decrease. When the soil is moderately dry, the surface is covered by a dense carpet of lichens (_Corniculariæ_), mixed in damper spots with Icelandic moss. In more tenacious soils, other plants flourish, not however to the exclusion of lichens, except in tracts of meadow ground, which occur in sheltered situations, or in the alluvial inundated flats where tall reed-grasses or dwarf willows frequently grow as closely as they can stand. [Illustration: 5. COAST OF LABRADOR.]