The invasive yellow iris originates from the Old World. It belongs to the large group of beardless irises--the same group where all of American irises belong. This group (Limniris) can be treated as either a subgenus of the genus Iris or a distinct genus. In any iris flower, the three largest, most conspicuous parts are the sepals. In all members of the alternative group of species, bearded irises, "beard," a line of multi-cellular trichomes (hairs), is found along proximal part of each sepal midrib. It is not present in this case, as this is a beardless species.