KARYOLOGICAL STUDY OF THE GENUS STEPTORHAMPHUS BUNGE (LACTUCEAE, ASTERACEAE)

In the present study the karyological characteristics of three species of genus Steptorhamphus Bunge have been described. Two populations of S. czerepanovii Kirp., one of S. persicus (Bioss.) O. et B. Fedtsch. and six of S. tuberosus (Jacq.) Grossh. have been examined. For each s pecies the morphological type, the total length of the chromosome pair s and the diploid set, the centromeric index and the index of the kary otype asymmetry have been determined. All species have stable chromoso me numbers: 2n = 16, but they are well differentiated karyotypically. S. persicus - 2n = 2M + 10SM + 2SA + 2SA(s), S. czerepanovii - 2n = 10 SM + 2SM(s) + 2SA + 2SA(s) and S. tuberous - 2n = 12SM + 2SM(s) + 2SA( s). These data were previously unknown.