Description: This native perennial wildflower is about 1–2½' tall, branching occasionally. The stems are light green and more or less hairy. The alternate leaves are up to 5" long and 3" across; they are oval, ovate, elliptic, or oblanceolate in shape, and crenate or dentate along the margins. The upper surface of each leaf has short appressed hairs and a slightly rough texture; it is medium to dark green. The base of each leaf tapers to a winged petiole that is sessile or clasps the stem.
The upper stems terminate in individual
flowerheads spanning 1-3" across. Each flowerhead consists of 8-20 ray florets
surrounding numerous tiny disk florets. The petal-like ray florets are golden
yellow to orange-yellow with notched tips; they spread outward from the center
of the flowerhead. In some plants, the base of each ray floret is maroon
(reddish brown), but this is atypical. The disk florets are dark brown or dark
purple and tubular-shaped. Each disk floret has 5 tiny lobes along its upper
rim that are erect, rather than spreading outward. Each 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.
Cultivation: The preference
is partial sun, moist conditions, and a fertile loamy soil with organic
material. At a dry sunny site, there is a tendency for the leaves to wilt and
the flowerheads may not develop properly. This coneflower tolerates more shade
than most others.
Range &
Habitat: Orange Coneflower is a rare wildflower that occurs in
scattered counties in the southern half of Illinois (see
Distribution
Map). This distribution applies to both var. fulgida and var.
deamii, but excludes var. sullivantii, which has been classified as
a distinct species, Rudbeckia sullivantii (Showy Coneflower), by
Mohlenbrock (2003). Habitats of Orange Coneflower include moist woodlands,
savannas, woodland openings and edges, meadows, limestone glades, and swamps.
Orange Coneflower is typically found in high quality natural areas.
Faunal
Associations: Like other Rudbeckia spp., the showy
flowerheads of Orange Coneflower attract their fair share of pollinating
insects. For example, the nectar of the flowerheads attracts various bees, bee
flies, small butterflies, and skippers; some bees also collect pollen for their
larvae. Other kinds of flies and beetles may visit the flowerheads as well;
they often eat pollen. The caterpillars of moths that feed on various parts of
Rudbeckia spp. include Chlorochlamys chloroleuca (Blackberry
Looper Moth), Eupithecia miserulata (Common Eupithecia), Synchlora
aerata (Wavy-Lined Emerald), and Homoeosoma electellum (Sunflower
Moth).
Photographic Location: The
wildflower garden of the webmaster in Urbana, Illinois. The photographed plant
is probably Rudbeckia fulgida deamii.
Comments: Orange Coneflower 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.
Individual plants can vary considerably in the shape and size of their leaves,
the size and color of their flowerheads, and the hairiness of their leaves and
stems. There are two varieties of Orange Coneflower that are recognized in
Illinois: Rudbeckia fulgida fulgida has smaller flowerheads (about
1–1½" across) and more narrow leaves that become significantly
smaller as they ascend the stems; Rudbeckia fulgida deamii has larger
flowerheads (about 1½–3" across) and more broad leaves that become
only slightly smaller as they ascend the stems. Orange Coneflower differs from
the closely related Rudbeckia sullivantii (Showy Coneflower) primarily
by the shape of its leaves: the varieties of the former have leaves with
crenate or dentate teeth, while the latter often has leaves that are shallowly
cleft. Orange Coneflower resembles the common Rudbeckia hirta
(Black-Eyed Susan) in appearance, but it can be distinguished from the latter
species as follows: 1) Its foliage is less hairy, 2) its leaves have petioles
that are conspicuously winged, 3) each of its achenes has a crown of tiny
teeth, and 4) it is a perennial. In contrast, Black-Eyed Susan has more hairy
foliage, its petioles lack conspicuous wings, its achenes are truncate at the
apex, and it is usually annual or biennial in habit. The leaves of Orange
Coneflower are often a darker shade of green and more broad in shape than those
of Black-Eyed Susan, although these distinctions are not always
reliable.