Taxonomic spectra of aboriginal and alien flora fractions in some sections of the Trans-siberian railway

An inventory of “railway” flora within 6 sectors of Trans-Siberian railway with a total length of 5400 km (58% of Transsib) was carried out. It was noted that both, native and alien fractions of the flora, are similar by high proportion of monospecific families and the Asteraceae lead. The alien fraction differs from the native one by a lower total number of families in the taxonomic spectrum, a lower rank of the Poaceae and a higher rank of the Brassicaceae. The leading families triads (the term developed by A.P. Khokhryakov for aboriginal flora of the former USSR) are not applicable for the characterization of the “railway” fl ora. The taxonomic spectrum of “railway” flora depends to a greater extent on (artificially created) edaphic factors than on climatic conditions of the territory which the railroad passes through.