The natural history of plants, their forms, growth, reproduction, and distribution; . to shatter the walls and to crack the stone by theirjfurther thickening. One at least out of the great number of instances may herenoticed. On either side of the little Tyrolese Gschnitz-thal are terraces strewn withlarge blocks of stone, which are considered ancient diluvial moraines. The blocks EFFECTS OF GKOWING CELLS ON ENVIRONMENT. 515 of stone are composed for the most part of crystalline schist, especially of gneiss, inwhich mica is arranged in almost parallel streaks. On one of these blocks (repre-sen
The natural history of plants, their forms, growth, reproduction, and distribution; . to shatter the walls and to crack the stone by theirjfurther thickening. One at least out of the great number of instances may herenoticed. On either side of the little Tyrolese Gschnitz-thal are terraces strewn withlarge blocks of stone, which are considered ancient diluvial moraines. The blocks EFFECTS OF GKOWING CELLS ON ENVIRONMENT. 515 of stone are composed for the most part of crystalline schist, especially of gneiss, inwhich mica is arranged in almost parallel streaks. On one of these blocks (repre-sented in fig. 130), at a height of 2 metres, a larch has long ago established itselfand rooted firmly, so that the strongest of its roots grow downwards in a cleftparallel to the direction of the mica streaks. By the thickening of this root thecrevice became widened; half of the upper block was separated from the lower andwas raised about 30 cms. It is estimated that the weight of this raised portionamounts to 1400 kg., and the root which was able to raise tliis Imi-den exhibits in. tig IJO —li,le\dtion of a Block of Stone in consequenLe of tlie ^lowth in tliickne»a of a Laitli Root its thickest part a diameter of only 30 cm. Moreover, the burden overcome by thislarch root is small in comparison with that raised by the roots of old trees. Thelarge superficial roots which creep over the ground of the forest like gigantic snakeswere not always situated in this position. As long as the trees were young theirroots extended under the ground. Only with increasing thickness did these roots,pressing against the firmly compacted earth lying beneath them, become visible aboveground, since they burst through the layer of earth situated above them. But withthis must also be connected the elevation of the whole trunk with its boughs, whichall bear upon the roots, and often weigh several thousand kilogrammes. It is a matter of course that growing stem-structures also exercise a considerable
Size: 1825px × 1370px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, booksubjectbotany, bookyear1902
