Coniferous forest formations, e.g., of Pinus sylvestris, Picea f~
FIR, the Scandinavian name originally given to the Scotch pine (Pinus sylvestris), but at present not infrequently employed as a general term for the whole of the true conifers (Abietineae); in a more exact sense, it has been transferred to the "spruce" and "silver firs," the genera Picea and A bies of most modern botanists.
In the spruce firs (Picea), the cones are pendent when mature and their scales persistent; the leaves are arranged all round the shoots, though the lower ones are sometimes directed laterally.
The most important of the firs, in an economic sense, is the Norway spruce (Picea excelsa), so well known in British plantations, though rarely attaining there the gigantic height and grandeur of form it often displays in its native woods.
- Norway Spruce (Picea excelsa).
Spruce Fir (Picea excelsa B, Cone and foliage.
The Norway spruce seems to have been the "Picea" of Pliny, but is evidently often confused by the Latin writers with their "Abies," the Abies pectinate of modern botanists.
The black spruce (Picea nigra) is a tree of more formal growth than the preceding.
- Norway Spruce (Picea excelsa).
The white spruce (Picea alba), sometimes met with in English plantations, is a tree of lighter growth than the black spruce, the branches being more widely apart; the foliage is of a light glaucous green; the small light-brown cones are more slender and tapering than in P. nigra, and the scales have even edges.
The wood is inferior to that of Picea excelsa, but, being soft and easily worked, is largely employed in the countries to which it is indigenous for all the purposes of carpentry.
Burgundy pitch is also prepared from it by a similar process as that from Picea excelsa.
Some of these are: Jack pine (Pinus Banksiana), Rocky Mountain pine (Pinus flexilis), black pine (Pinus Murrayana), white spruce (Picea alba), black spruce (Picea nigra), Engelman's spruce (Picea Engelmanni), mountain balsam (Abies subalpina), Douglas fir (Pseudotsuga Douglasii), mountain larch (Larix Lyallis).
Veronica crinita, Pinus leucodermis, Picea omorica and Daphne Blagayana.
The fir appears in the Siberian varieties Picea obovata and P. ayanensis.
Forests of conifers (Picea obovata) and deciduous trees - Przhevalsky's poplar, birch, mountain ash, &c., and a variety of bushes - are common everywhere.
Picea - Spruce Fir.
Picea obovata is cultivated.
- Cone of Picea alba a rosette, as in Sempervivum.
The species of timber almost exclusively planted are the red fir (Picea excelsa) and the mountain pine (Pinus montana).
Of the Coniferae, Podocarpus and Pinus longifolia alone descend to the tropical zone; Abies Brunoniana and Smithiana and the larch (a genus not seen in the western mountains) are found at 8000, and the yew and Picea Webbiana at 10,000 ft.
In the less exposed localities, on northern slopes and sheltered valleys, the European forms become more numerous, and we find species of alder, birch, ash, elm, maple, holly, hornbeam, Pyrus, &c. At greater elevations in the interior, besides the above are met Corylus, the common walnut, found wild throughout the range, horse chestnut, yew, also Picea Webbiana, Pinus, excelsa, Abies Smithiana, Cedrus Deodara (which tree does not grow spontaneously east of Kumaon), and several junipers.
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.
Picea excelsa var.
Abies pectinata, &c.) the ripe cone differs from those of Pinus, Picea and Cedrus in the large size of the carpellary scales, which project as conspicuous thin appendages beyond the distal margins of the broader and more woody seminiferous scales; the long carpellary scale is a prominent feature also in the cone of the Douglas pine (Pseudotsuga Douglasii).
Pinus and Picea) - in which the cone-scales persist for some time after the seeds are ripe - the cones hang down and so facilitate the fall of the seeds; in Cedrus, Araucaria and Abies the scales become detached and fall with the seeds, leaving the bare vertical axis of the cone on the tree.
A pine needle grown iji continuous light differs from one grown under ordinary conditions in the absence of hypodermal fibres, in the absence of the characteristic infoldings of the mesophyll cell-walls, in the smaller size of the resin-canals, &c. The endodermis in Pinus, Picea and many other genera is usually a well-defined layer of cells enclosing the vascular bundles, and separated from them by a tissue consisting in part of ordinary parenchyma and to some extent of isodiametric tracheids; but this tissue, usually spoken of as the pericycle, is in direct continuity with other stem-tissues as well as the pericycle.
It has been suggested that transfusion-tracheids represent, in part at least, the centripetal xylem, which forms a distinctive feature of cycadean leaf-bundles; these short tracheids form conspicuous groups laterally attached to the veins in Cunninghamia, abundantly represented in a similar position in the leaves of Sequoia, and scattered through the so-called pericycle in Pinus, Picea, &c. It is of interest to note the occurrence of precisely similar elements in the mesophyll of Lepidodendron leaves.
In northern Europe this belt is characterized by such species as Picea excelsa (spruce), which extends south to the mountains of the Mediterranean region; Pinus sylvestris (Scottish fir), reaching from the far north to western Spain, Persia and Asia Minor; Juniperus communis, &c. In north Siberia Pinus Cembra (Cembra or Arolla Pine) has a wide range; also Abies sibirica (Siberian silver fir), Larix sibirica and Juniperus Sabina (savin).
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.
In the Mediterranean region occur Cupressus sempervirens, Pinus Pinea (stone pine), species of juniper, Cedrus atlantica, C. Libani, Callitris quadrivalvis, Pinus montana, &c. Several conifers of economic importance are abundant on the Atlantic side of North America - Juniperus virginiana (red cedar, used in the manufacture of lead pencils, and extending as far south as Florida), Taxodium distichum (swamp cypress), Pinus rigida (pitch pine), P. mitis (yellow pine), P. taeda,P. palustris, &c. On the west side of the American continent conifers play a still more striking role; among them are Chamaecyparis nutkaensis, Picea sitchensis, Libocedrus decurrens, Pseudotsuga Douglasii (Douglas fir), Sequoia sempervirens, S.
The coniferous zone begins, characterized by the Picea Schrenkiana.