2110 AKbOKETUM AND FllUTlCETl'M. 1'AIITIII. 



and seldom more in Araucaria imbricata. In Pinus inops there are four 

 cotyledons ; in P. sylvestris from five to seven ; in J v bies excelsa there are 

 from three to nine ; in Z/arix europae^a from five to seven ; in Pinus Strobus 

 eight ; in Cedrus Libani from nine to eleven ; and in Pinus Pinea from ten to 

 twelve. 



The general structure of the ^bietinae is remarkable for its unity. The 

 vessels, both in the leaves and wood, are straight and parallel; the trunk is 

 straight, and the branches and all their subdivisions straight and parallel also. 

 Even the leaves, whether inserted in rows as in the firs, or irregularly round 

 the stem as in the spruces and pines, all stand: out parallel, and at right an- 

 gles to the branches. The branches form whorls ; and so do the leaves of 

 the cotyledons. The shape of the fruit is conical, and so is that of the entire 

 tree. 



The rate of growth of the -<4bitinae is, in general, rapid ; and the duration of 

 the tree, compared with that of the oak, short. The most rapid-growing 

 species in the climate of London is the Pinus Laricio, which will attain the 

 height of 20 ft. in 10 years; and the species of this section generally reach 

 maturity, in the climate of Britain, in from 60 to 100 years. Most of the 

 European species bear cones at about 20 years' growth, or before ; the spruce 

 fir, on dry chalky soils, in less than half that period. The pinaster arrives at 

 maturity sooner than any other European pine, but seldom lasts longer than 

 from 40 to 50 years. The European species of slowest growth, and greatest 

 duration, is the P. Cembra, which seldom attains more than 30 ft. or 40 ft. in 

 height, but which lives for several centuries. The two species which in 

 Europe are most valuable for their timber are the P. sylvestris and the iarix 

 europae N a. The grandest and most ornamental species is, unquestionably, the 

 Cedrus Libani, and the most elegant and graceful the ^4 y bies canadensis. The 

 species which produce the greatest quantity of timber in the shortest time, in 

 the climate of Britain, are the Scotch pine and the larch ; but in favourable 

 situations, both in Germany and Switzerland, these species are exceeded in 

 this respect by the silver fir ; in Spain by the pinaster ; and in North America 

 by the Weymouth pine. 



The greater number of the species of ^bietinae will live in the open air in 

 the climate of London ; but some few require to be protected there from the 

 frost. 



Geography. The Jbietinas enjoy an extensive range, but chiefly in the 

 temperate parts of the northern hemisphere. Some species are found, both 

 in Europe and America, so far north as to be bordering on the regions of 

 perpetual snow ; and others, in Central Europe and in Asia, on the Alpine 

 and Himalayan mountains, in places where, from their great elevation, the 

 climate is equally cold. Wahlenberg and Von Buch describe the genus Pinus 

 as occupying the extreme limits of arborescent plants, on Mont Blanc and 

 Mont Perdu, lat. 42 46' and on Solitinia, in Lapland, lat. 68. Next to 

 Pinus, the genus arix approaches the nearest to the line of snow. (Ed. 

 Phil. Journ., i. p. 316.) The ^bies disappears on these mountains about 

 400 ft. lower than Pinus, the species of which extend to within 2800 ft. of 

 the line of perpetual snow. The mean temperature necessary for A^bies is 

 37^, while that for Pinus is only 36. On the mountains of Mexico, Hum- 

 boldt and Bonpland found the genus Pinus always attaining the extreme 

 limits of arborescent plants, in the same manner as it does in Europe ; P. 

 australis Michx. they found occupying a zone at the height of 6000 ft. on 

 Popoc. Lieutenant Glennie, R. N., who ascended the mountain of Popo- 

 cotapetl, in April, 1827, describes the sides of the mountain as thickly 

 wooded with forests of pines, extending to the height of nearly 12,693 ft., 

 beyond which altitude vegetation ceased entirely. The ground consisted of 

 loose black sand of considerable depth, on which numerous fragments of basalt 

 and pumice stone were dispersed. (Proc. of the Geol. Soc. ofLond., No. vi. 

 p. 76., for 1827-8.) In the southern hemisphere, the yfbi&inae have not been 

 found beyond lat. 18 or 20. The greater number of them are indigenous 



