Estudios Cariotípicos en Flourensia (Asteraceae) de Argentina

Summary: Karyotypic studies in Flourensia (Asteraceae) from Argentina. Twelve species of the American genus Flourensia DC. inhabit Argentina. Six of them grow in its central region, all endemic to it. Chromosomal number is known for most species, but no karyotypic studies have been done. Therefore, we studied the mitotic chromosomes of the six Central Argentinean species, performing qualitative and quantitative analysis of their karyotypes. Permanent mounts were made from root tips with classical techniques. All species had 2n=36: three with 14 m + 4 sm pairs and the remaining with 12 m + 6 sm pairs. The average chromosome length varied between 2.11 and 2.97 mm. Statistical differences were found for the variables C, Lt, R, and A 1 . Except for F. campestris, one or two pairs of satellites which varied in their location were found. The data obtained have taxonomic value since differences were found among nearly all species, suggesting that their speciation would have been accompanied by small chromosomal changes caused by inversions and/or translocations.