The presence in the Netherlands of three taxa of the Juncus bufonius complex with different ploidy levels was established: a diploid one with 2n = 34. a tetraploid with 2n about 70, and a hexaploid with 2n 100-110. The taxa in question can be distinguished by several morphological characteristics, and they exhibit in addition differences in their distribution and ecology. They are here tentatively referred to J. ranarius (2n 34). J. minutulus (2n c. 70) and J. bufonius s.str.. 2n 100-110.