5. The sub-alpine zone, between the elevation of 6,000 and 7,500 feet, produces the barberry, soap-wort, toad-flax, and juniper. 6. The zone between 7,500 and 9,000 feet, has almost all the plants of the preceding, with the fleshy and jagged groundsel. [Verse: "In the mountain of the height of Israel will I plant it; and it shall bring forth boughs, and bear fruit, and be a goodly cedar: and under it shall dwell all fowl of every wing; in the shadow of the branches thereof shall they dwell."--EZEKIEL XVII.] 7. The narrow zone between 9,000 and 9,200 feet, only produces a few lichens, beyond which, there is complete sterility. 1241. The Peak of Teneriffe exhibits five botanical districts, thus distinguished by Von Buch: 1. The region of Africa forms, 0--1,248 feet, comprising palms, bananas, the sugar-cane, various species of arborescent _Euphorbiæ_, _Mesembryanthema_, the _Dracæna_, and other plants, whose naked and tortuous trunks, succulent leaves, and bluish-green tints, are distinctive of the vegetation of Africa. 2. Region of Vines and Cereals, 1,248--2,748 feet, comprising also the olive, and the fruit-trees of Europe. 3. Region of Laurels, 2,748--4,350 feet, including lauri of four species, the wild olive, an oak, the iron-tree, the arbutus, and other evergreens. The ivy of the Canaries and various twining shrubs cover the trunks of the trees, and numerous species of fern occur, with beautiful flowering plants. 4. Region of the Pines, 4,350--6,270, characterised by a vast forest of trees resembling the Scotch fir, intermixed with juniper. 5. Region of the Retama, 6,270--11,061 feet, a species of broom, which forms oases in the midst of a desert of ashes, ornamented with fragrant flowers, and furnishing food to the goats, which run wild on the Peak. A few gramineous and cryptogamic plants are observed higher, but the summit is entirely destitute of vegetation. 1242. There are many plants which can accommodate themselves to the most diverse climates and localities; and therefore ascend from the plains close to the boundary of vegetable life on the highest mountains. But it is the general law in these cases for such plants to be singularly modified in appearance and anatomical structure as they ascend. The spring gentian, _Gentiana verna_, is one of the exceptions, which Raymond found unaltered at all heights in the Pyrenees.