Tree vegetation, which reaches up as high as 6500 and 8150 ft., the latter limit on the north and west, consists of magnificent forests of birch, poplar, aspen, and Coniferae, such as Pinus cembra, Abies sibirica, Larix sibirica, Picea obovata, and so on, though the fir is not found above 2500 ft., while the meadows are abundantly clothed with brightlycoloured, typical assortments of herbaceous plants.
In Larix the axis of the cone often continues its growth; similarly in Cephalotaxus the cones are often proliferous.
Venice turpentine is yielded by the larch tree, Larix europaea, from which it is collected principally in Tirol.
The members of the genus Larix are distinguished from the firs, with which they were formerly placed, by their deciduous leaves, scattered singly, as in Abies, on the young shoots of the season, but on all older branchlets growing in whorl-like tufts, each surrounding the extremity of a rudimentary or abortive branch; they differ from cedars (Cedrus), which also have the fascicles of leaves on arrested branchlets, not only in the deciduous leaves, but in the cones, the scales of which are thinner towards the apex, and are persistent, remaining attached long after the seeds are discharged.
Boletus edulis, in the Oriental Trehala and in ergot of rye; melibiose, C12H22011, formed, with fructose, on hydrolysing the trisaccharose melitose (or raffinose), C18H32016.5H20, which occurs in Australian manna and in the molasses of sugar manufacture; touranose, C12H22011, formed with d-glucose and galactose on hydrolysing another trisaccharose, melizitose, C,8H32016 2H20, which occurs in Pinus larix and in Persian manna; and agavose, C12H22011, found in the stalks of Agave americana.
In the North American area Picea alba, P. nigra, Larix americana, Abies balsamea (balsam fir), Thuja canadensis (hemlock spruce), Pinus Strobus (Weymouth pine), Thuja occidentalis (white cedar), Taxus canadensis are characteristic species.
A pine cone reaches maturity in two years; a single year suffices for the full development in Larix and several other genera.