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Show 342 PHYSIOGNOMY OF PLANTS. direction through eighty degrees of longitude (above 3040 geographical miles), from the mouth of the Scheidt through Europe and the north of Asia to Bogoslowsk in the northern Ural and Barnaul beyond the Obi, I have found differences in the length of the needles of our common Fir (Pinus sylvestris) so great, that sometimes a traveller may be misled, by the shortness and rigidity of the leaves, to think that he has discovered a new species allied to the Mountain Pine, P. rotundata (Link), P. uncinata (Ram.). Link has justly remarked (Linnrea, bd. xv. 1841, s. 489) that such instances may be regarded as transitions to Ledebour's P. sibirica of the Altai. In the Mexican highlands, I have looked with particular pleasure on the delicate cheerful green of the Ahuahuete, Taxodium distichum (Rich.), Cupressus disticha (Linn.), which, however, is much given to shedding its leaves. In this tropical region, the above-mentioned tree (of which the Aztec name signifies waterdrum, from atl, water, and huehuetl, a drum, the trunk swelling to a great thickness) flourishes 5400 and 7200 (5755 and 7673 English) feet above the level of the sea j while in the United States of North America it is found in the low grounds of the cypress swamps of Louisiana, in the 43d parallel. In the Southern States of North America, the Taxodium distichum (Cypres chauve) reaches, as in the Mexican highlands, the height of 120 (128 English) feet, and the enormous thickness of 30 to 37 (32 to 39 English) feet, measured near the ground. (Emerson, Report on the Forest, pp. 49 and 101.) The roots present the striking phenomenon of woody excrescences which project from 3 to 4t feet above the earth, and are conical and rounded, and sometimes tabular. Travellers have compared these excrescences in places where they are very numerous to the grave tablets in a .Jewish burying-ground. Auguste de St.-Hilaire remarks with much acuteness: '' Ces excroissances du Cypres chauve, resemblant a des bornes, peuvent etre regardees comme des exostoses, et comme elles vivent dans l'air, il s'en echapperoit sans doute des bourgeons adventifs, si la nature du tissu des plantes coniferes ne s' opposoit au developpement des germes caches qui donnent naissance a ces sortes de bourgeons." (Morphologie vegetable, p. 91.) A singularly enduring power of vitality in the roots of trees of this family is shown by a phenomenon which has excited the |