When the ground is crusted with a hard and frozen snow, which prevents it from obtaining its usual food, the reindeer turns to another lichen, called rock-hair (_Alectoria jubata_), that grows in long bearded tufts on almost every tree. In winters of extreme rigour, the Laplanders cut down whole forests of the largest trees, that their herds may browse freely on the tufts which clothe the higher branches. Hence it has been justly said that “the vast dreary pine-forests of Lapland possess a character which is peculiarly their own, and are perhaps more singular in the eyes of the traveller than any other feature in the landscapes of that remote and desolate region. This character they owe to the immense number of lichens with which they abound. The ground, instead of grass, is carpeted with dense tufts of the reindeer moss, white as a shower of new fallen snow; while the trunks and branches of the trees are swollen far beyond their natural dimensions with huge, dusky, funereal branches of the rock-hair, hanging down in masses, exhaling a damp earthy smell, like an old cellar, or stretching from tree to tree in long festoons, waving with every breath of wind, and creating a perpetual melancholy sound.” * * * * * In regions furthest north are found various species of lichens belonging to the genera _Gyrophora_ and _Umbilicuria_, and known in the records of Arctic travel as rock tripe, or _tripe de roche_; a name given to them in consequence of their blistered thallus, which bears a faint resemblance to the animal substance so called. They afford a coarse kind of food, and proved of the greatest service to the expeditions under Sir John Franklin; though their nutritious properties are not considerable, and, such as they are, are unfortunately impaired by the presence of a bitter principle which is apt to induce diarrhœa. In Franklin and Richardson’s terrible overland journey from the Coppermine River to Fort Enterprise it was almost the sole support, at one time, of the heroic little company. Dr. Richardson says they gathered four species of _Gyrophora_,[9] and used them all as articles of food; “but not having the means of extracting the bitter principle from them, they proved nauseous to all, and noxious to several of the party, producing severe bowel complaints.” Franklin on one occasion remarks: “This was the sixth day since we had enjoyed a good meal; the _tripe de roche_, even when we got enough, only serving to allay the pangs of hunger for a short time.” Again, we read: “The want of _tripe de roche_ caused us to go supperless to bed.”