The first checklist of alien vascular plants of Kyrgyzstan, with new records and critical evaluation of earlier data. Contribution 3

All records of <i>Hesperismatronalis</i> in Central Asia (including Kyrgyzstan) belong to <i>H.pycnotricha</i>; the latter species is newly reported as a locally naturalised alien in Kazakhstan. The previous record of <i>Sisymbriumirio</i> from Kyrgyzstan is rejected as based on a misidentified specimen of <i>S.loeselii</i>, but the species is newly recorded here as a recent casual alien. <i>Hirschfeldiaincana</i> is presumably native in south-western Turkmenistan; its second record in Central Asia was caused by the import of contaminated wheat grain in the times of the Soviet grain crisis and its recent expansion may be linked to the increasing import of forage grain. The introduction of <i>Crambeorientalis</i> was connected with its cultivation for fodder and as an ornamental plant and its further broad dispersal was aided by winds. <i>Rorippaaustriaca</i> is native in the steppes of north-western Kazakhstan, but alien in the mountains of Central Asia. The occurrences of three alien species originated directly from cultivation (<i>Hesperispycnotricha</i> as an ornamental, <i>Armoraciarusticana</i> as an edible plant, <i>Crambeorientalis</i> as an ornamental and fodder plant), three species (<i>Hirschfeldiaincana</i>, <i>Mutardaarvensis</i>, <i>Sisymbriumirio</i>) were imported as grain contaminants, whereas two others (<i>Rorippaaustriaca</i>, <i>R.sylvestris</i>) have arrived with contaminated soil on ornamental plants or arboreous saplings. The arrival period is inferred as the Neolithic period (<i>Mutardaarvensis</i>), the Imperial times (<i>Armoraciarusticana</i>, <i>Hesperispycnotricha</i>), the post-war Soviet times (<i>Crambeorientalis</i>, <i>Rorippaaustriaca</i>, <i>R.sylvestris</i>) and the independence times (<i>Hirschfeldiaincana</i>, <i>Sisymbriumirio</i>). All the treated species, but two, increase their frequency in Kyrgyzstan; <i>Mutardaarvensis</i> has already reached its complete distribution, being an ubiquitous weed, whereas <i>Armoraciarusticana</i> experiences a projected decline because its common cultivation has ceased. No species is invasive in natural habitats. A new combination, Mutardaarvensisvar.orientalis (L.) Sennikov, is proposed for a variant with pubescent pods.