This native perennial plant is about 2-3' tall and unbranched, except for the flowering stalks near the apex. Missouri Goldenrod produces both flowering and non-flowering shoots. The central stem is light green to dark red, terete (round in circumference), and hairless; the lower portion of this stem may become slightly woody with age. The alternate leaves are up to 5" long and ¾" across, becoming smaller as they ascend the central stem. They are narrowly lanceolate, narrowly oblanceolate, or elliptic in shape, and serrated along their margins. Each leaf usually has 3 parallel veins (a central vein & 2 lateral ones) and tapers to a petiole-like base; however, on some upper leaves, only the central vein may be prominent. Both the upper and lower sides of each leaf are hairless. From the axils of the middle to upper leaves, short secondary stems may develop with tufts of alternate leaves; these secondary stems often fail to produce flowers. A panicle of yellow flowerheads develops at the apex of fertile shoots, spanning up to 6" long and 4" across. This panicle has recurved flowering stalks that are either hairless or hairy. Each flowerhead is about 1/8" across; it consists of several yellow disk florets that are surrounded by about 6-12 ray florets. At the base of each flowerhead, there are green to yellowish green floral bracts in an overlapping series; these tiny bracts are linear-oblong. The blooming period usually occurs from mid-summer to early fall and lasts about a month for a colony of plants. Each floret is replaced by a bullet-shaped achene with a small tuft of white hairs; distribution of the achenes is by wind. The root system produces fibrous roots and rhizomes; some older plants may produce a small caudex. Missouri Goldenrod reproduces vegetatively by offsets and sexually by seeds; it often forms sizable vegetative colonies in which only the outer shoots are fertile and produce flowers. The inner shoots of such colonies are infertile and usually smaller in size.