less than 20 spp. (of 8 subgenera) in our area, of which 3 imported to control weeds, 3 adventive; huge group with ~450 spp. and hundreds of sspp. in 65 subgenera (23 of which monotypic) in the Old World(2)(3)
Range
Eurasia (~90% of total spp.), Africa, NA; our native spp. are mostly boreal/montane(2)(3)