Flower:

Flowers are short-stalked, arising singly from leaf axils and at the tips of branches but numerous on a plant, egg to bell shaped, up to ½ inch long. with up to 8 short, deep yellow rays (petals), usually about 5, spreading out at the top around the yellow center disk flowers. The 4 to 9 outer bracts are green, linear, flaring at the tip, 2/3 the length of inner bracts, which are broader and very papery, greenish-orange to purplish in color. These inner bracts each have 1 or more orangish glands scattered on the surface.

Leaves and stems:

Leaves are mostly opposite, may be alternate in the upper plant, ¾ to 2 inches long and deeply divided into linear lobes, which may be further divided, lobed, or with a few coarse teeth around the edges. Leaves are hairless to sparsely hairy.

Orange-brownish glands dot the foliage which has a spicy pungent odor (not necessarily unpleasant) when crushed. Stems are mostly erect with diffuse branching, finely hairy to nearly smooth throughout.

Fruit:

Fruit is a dry seed up to 3.5 mm long, narrowly conical, densely hairy, dark brown at maturity with a tuft of bristly hairs at the tip.

Notes:

Fetid Marigold is native throughout much of the western and south-central Great Plains but is considered adventive (not completely naturalized) in Missouri eastward (including Minnesota), with scattered introductions up into New England as well as west to Utah and Arizona. Collected as early as 1888 in Rock County, it wasn't recorded again until nearly 100 years later, in Houston County. In the summer of 2012 we encountered it in Winona County and a friend found it in Scott. It is small and weedy so can be easily overlooked elsewhere, but it's certain to say it's on the move, typically along the road shoulders of our extensive transportation system.

Case in point: during our travels over the past several years we started noticing patches of a low, dense, yellowish-green plant more and more, particularly common in the median shoulder of I35. We soon discovered it was Fetid Marigold and, between 2015 and 2016, tracked it along highways in more than 20 counties. It's probably safe to say it's here to stay.