Abstract
THE July number of the Proceedings of the Royal Geographical Society contains a detailed report of the paper read by Dr. Junker on his explorations in Central Africa. Mr. Delmar Morgan contributes, from Russian sources, a long account of Russian geographical work in 1886, which contains much that is interesting. One of the most important Expeditions was that under J. V. Ignatieff, to explore the magnificent Khan Tengri group of mountains in the Thian Shan, whose summits soar to a height of 22,000 to 24,000 feet. The botanist of the Expedition, A. N. Krasnof, made some extremely important investigations, with especial reference to the flora of the high snow and ice regions of the Thian Shan, as compared with that of the Polar regions recently worked up by Wittrock. M. Krasnof is of opinion that the valley of the Ili once had an entirely different vegetation to that possessed by it now, and that this early plant-life has completely perished owing to the desiccation of Central Asia and the consequent change in its climate. Formerly, M. Krasnof says, the whole flora of the Ili valley was similar to that still preserved at the foot of the snowy mountains, resembling that of Central Russia. At present all the lower chains are deprived of the moisture they derived from melting ice-fields, and have changed their flora in the most radical way, having now only Central Asian forms. M. Krasnof's general conclusions are that formerly the Thian Shan flora was intermediate between the Altai and the Alpine, and resembled more closely that of the Central and Northern Caucasus. The process of desiccation began in the south, and showed itself by the formation of detritus, retreat of the glaciers, and disappearance of lakes. It caused the formation of loess deposits, sand, and pebble-strewn plains, while it diminished the areas of marshes and black-earth deposits. All plants common to Polar and Alpine regions disappeared from the southern slopes and syrts, while coniferous and deciduous arborescent vegetation also vanished from all waterless slopes. Wherever the snow has ceased to lie, the ancient flora has also perished, only a few species having adapted themselves to a continental climate and assumed an Asiatic character.
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Geographical Notes . Nature 36, 257–258 (1887). https://doi.org/10.1038/036257b0
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DOI: https://doi.org/10.1038/036257b0