Abstract
Several weed species are considered to be of minor importance as rangeland weeds because of the number of acres they infest. Although they are not found in extremely large numbers, control of Dalmatian toadflax (Linaria gertistifolia ssp. dalmatica), yellow toadflax (Linaria vulgaris), black henbane (Hyoscyamus niger), tansymustard (Descurainia pinnata) or flixweed (Descurainia sophia) is important in range management because of their potential to spread and create a detrimental impact on wildlife, livestock, and man. Dalmatian and yellow toadflax are perennial weeds that reproduce by seeds and creeping roots. Black henbane is an annual or biennial, and tansymustard and flixweed are annuals. All of these species have the ability to produce large numbers of seed that can spread by wind or animals. Seed from these weeds also can lie dormant in the soil for several years. One factor these weed species have in common is that they establish themselves most readily on disturbed and/or poorly maintained soils. All of these weeds are somewhat to very opportunistic and are generally found along roadsides, waste areas, and poorly managed pastures and rangeland. These weeds can be found throughout most of North America. Dalmatian and yellow toadflax will grow in more humid areas than black henbane, 400tansymustard, or flixweed. Tansymustard and flixweed tend to favor the less humid climates. Black henbane would be considered the most dangerous plant to animals because of its toxic properties. However, because of its foul odor, it is not readily grazed and probably does not cause any more of a problem to animals than the other weed species. Dalmatian and yellow toadflax are the most difficult of these weeds to control because of their perennial life cycle. Black henbane, tansymustard, and flixweed can be effectively controlled with chemicals as well as by hoeing or cultivation where possible.