Two autotetraploids (2n = 4x = 24) were produced by colchicine treatment of dry seeds ofLotus tenuisWaldst. et Kit. Triploids (2n = 3x = 18) were obtained by backcrossing the tetraploids to normal diploid plants. Primary trisomies (2n = 12 + 1) were obtained by selfing the triploids. A morphological comparison was made between a randomly selected diploid, a tetraploid, and five trisomic plants. The trisomics could be distinguished distinctly from the diploid and tetraploid using 12 quantitative phenotypic traits. Two traits, bract index and number of flowers per umbel, were not significantly different between all three cytotypes (2x, 2x + 1, 4x). By means of morphological analyses it was possible to select trisomic plants for presumably different trisomes prior to detailed cytological analyses of individual chromosomes.Key words: aneuploidy, tetraploids, Fabaceae,Lotus tenuis, morphological traits, triploids, primary trisomics.