Orange Coneflower (Rudbeckia fulgida
) is quite variable in appearance from one site to another. Consequently, this species has been a source of taxonomic problems that continues to this day. Some authorities classify Orange Coneflower as a single species consisting of several varieties, while others regard it as a complex of several closely-related species. Here, Sullivant's Coneflower is treated as a variety of Orange Coneflower. Sullivant's Coneflower can be distinguished from these other varieties by its larger flowerheads (typically 2-3" across) and the shape of its leaves. Other varieties of Rudbeckia fulgida
that may be encountered in Illinois include
This perennial wildflower is about 1½-2½' tall, branching occasionally. Low basal leaves are produced initially that are oval in shape and dentate along their margins; their bases are rounded to slightly cordate. Later, stems are produced that are light green with spreading white hairs. The alternate leaves are up to 5" long and 2½" across, becoming smaller and more narrow as they ascend the stems. Alternate leaves are ovate, broadly elliptic, or elliptic in shape, and dentate along their margins. The upper surface of each leaf is either hairless or sparsely covered with short appressed hairs; it is medium to dark green. The base of each alternate leaf tapers to a winged petiole; the base of the petiole is either sessile or clasps the stem. The upper stems terminate in individual flowerheads spanning 2-3" across. Each flowerhead consists of 10-20 ray florets surrounding numerous tiny disk florets. The petal-like rays of the ray florets are yellow to orange-yellow with notched tips; they spread outward from the center of the flowerhead. The tiny disk florets are dark brownish purple and tubular-shaped. Each disk floret has 5 tiny lobes along its upper rim that are erect, rather than spreading outward. Each disk floret has a divided style with blunt tips. The blooming period occurs from mid-summer into the fall and lasts about 2 months. The mature achenes are oblongoid, 4-angled, and black; the upper end of each achene is truncate with a minute crown of tiny teeth (the pappus). Each achene is about 3 mm. in length or a little less. These achenes are light weight and can be blown about by the wind, but they usually don't stray far from the mother plant. The root system is fibrous and rhizomatous. In open disturbed areas, vegetative colonies are often formed from the rhizomes.