First karyotype description and nuclear 2C value for (Primulaceae): comparing three species.

Cytogenetic studies in Primulaceae are mostly available for herbaceous species, and are focused on the chromosome number determination. An accurate karyotype characterization represents a starting point to know the morphometry and class of the chromosomes. Comparison among species within , associating these data with the nuclear 2C value, can show changes that led the karyotype evolution. Here, we studied three species [ (Swartz, 1788) Brown ex Roemer et Schultes, 1819, Martius, 1841 and Candolle, 1841] that show different abilities to occupy the varied types of vegetation within the Brazilian Atlantic Forest. Cytogenetic characterization showed some individuals with 2n = 45 chromosomes for and , with most individuals of the three species having 2n = 46. The first karyograms for were assembled and presented morphologically identical and distinct chromosome pairs. In addition, differences in the mean 2C nuclear value and chromosome morphometry were found. Therefore, the first description of the karyotype has been presented, as well as the nuclear 2C value. The procedures can be applied to other species for future investigations in order to better understand its effects on the differential spatial occupation abilities shown by the species in Brazilian Atlantic Forest.