Abstract
Karyotypes and meiosis in 13 species of the genus Fimbristylis have been studied. Karyotypes in F. acuminata (2n=10), F. barbata (2n=10), F. bisumbellata (2n=10), F. cinnamometorum (2n=10), F. complanata (2n=10), F. argentea (2n=20) and F. spathacea (2n=48) have been studied for the first time. The most widely represented basic number is x=5. Cytological data suggest the primitive status of this genus in Cyperaceae. Both structural changes and polyploidy seem to have played a major role in the evolution and speciation in Fimbristylis.
