GEOGRAPHICAL DISTRIBUTION OF PLANTS. 555 
European Leadwort, the Juniper, the great Lurphorbia eharacis, 
the Psoralea, of bituminous odour, &e. 
“A region altogether destitute of arborescent vegetation follows. 
The soil is here naked, stony, and generally uncultivated ; never- 
theless, here and there fields of chick peas, oats, and barley appear, 
the last of which disappears at three thousand five hundred feet 
above the Mediterranean ; but a shrub—the Box Tree—two under- 
shrubs—Thyme and lLavender—another herbaceous Labiate 
(Nepeta graveolens), and the Swallow-wort (Vincetoxicum offici- 
nalis), predominate as to size and number. | It is at this point that 
the first indications of an arborescent vegetation appear, but it is 
necessary to ascend to three thousand eight hundred feet before 
reaching the new vegetation. It is composed of Beeches; at 
first. sparse and undersized, they get larger three hundred feet 
higher, especially in the deep ravines and valleys, where they are 
sheltered from the wind. This region extends as high as five 
thousand five hundred feet. At this height the depressions: are 
slight; valleys and ravines almost cease, and the trees are ex 
to the depressing action of the winds. The plants which clothe the 
soil are now humble bushes, with! short, hard, and crowded ~ 
branches. One of these bushes, like a large ball or mattrass ex- 
tended on the earth, is often as’ old:as the great Beeches which 
elevate their proud heads to the heavens in the valleys below. 
‘Numerous species occupy the region of Beeches, many of them be- 
longing to the sub-alpine zone of the mountains of central Europe, 
never descending into the plains, unless transplanted. Such are 
' the Buckthorn, the Gooseberry, the Wallflower, the Mountain 
Sorrel, and the mountain Anthylis. 
“At the height of five thousand six hundred feet the cold is 
intense, the summer brief, and the wind so violent that the Beech 
can no longer exist. As upon Mount Ventoux, so it is on the Alps 
and Pyrenees,—on all, a tree of the family of Conifers is the last 
representative of arborescent vegetation. Itis a humble species of 
pine, called the Mountain Pine (Pinus uncinata), because the scales 
of its cone are curved into a sort of claw. These Pines are found 
many feet in height in sheltered places, but become mere bushy 
shrubs when exposed to the sweep of the winds. They ascend as high 
as six thousand fect, the extreme limit of arborescent vegetation. 
