Chondrilla

 Preliminary data on the genome size of representatives of the genus Chondrilla (Asteraceae) of European Russia and Western Kazakhstan were obtained using fl ow cytometry. Among all studied specimens of the genus, for specimens of C. ambigua and C. pauciflora, a direct dependence of the genome size on the number of chromosomes was established. In our study, the DNA content of the diploid C. ambigua was 2С = 1.69 pg, and that of the triploid C. pauciflora was 2С = 2.65 pg.

The morphological variability in populations of Chondrilla was subject to the numerical analysis using the unweighted pair group method with arithmetic mean (UPGMA). The study showed that out of the seven species of the genus found in European Russia, it is only C. ambigua that has the status of undoubted species. A distinct difference is observed between the two groups of populations: the first group comprising C. juncea, C. latifolia, C. brevirostris, and the mixed population of C. juncea/graminea; and the second group comprising the populations of C. graminea and C.

The monitoring of the frequency of apomixis was making in popu- lations of 7 species of Chondrilla in the south of european part of Russia. It is shown that the plants of 6 examined species (C. juncea, C. graminea, C. canescens, C. brevirostris, C. latifolia и C. acantho- lepis) are characterized by their ability to seed reproduction by apo- mixis. This fact is confirmed by results of a study of seed productivity of the species of the genus Chondrilla at the regime of blossoming without pollen and cytoembryological analysis megagametophytes of the same plants.