71. Echinacea Moench
(coneflower)
(McGregor, 1968;
Binns et al., 2002)
Plants perennial
herbs, with a usually elongated, vertical rootstock and often somewhat tuberous
main roots (merely fibrous-rooted in E. purpurea), sometimes also with
short, stout rhizomes. Stems erect or ascending, unbranched or few- to
several-branched, with several longitudinal lines or ridges, variously hairy
(glabrous elsewhere), usually roughened to the touch. Leaves basal and
alternate, the basal and lower stem leaves long-petiolate, the petioles
progressively shorter up the stem, the upper stem leaves sometimes sessile or
nearly so, the bases usually only slightly expanded, those of the basal and
lower stem leaves usually somewhat wrapping around the stem. Leaf blades
simple, linear to lanceolate, elliptic, or ovate, tapered at the base (those of
the basal leaves rounded to heart-shaped in E. purpurea), mostly tapered
to a sharply pointed tip, the margins entire or irregularly toothed, the
surfaces roughened-hairy, not glandular, with 3 or 5 main veins. Inflorescences
of solitary terminal heads, the heads with long, bractless stalks. Heads
radiate. Involucre broadly cup-shaped or saucer-shaped, the bracts in mostly 2–4
subequal, overlapping series. Involucral bracts about 17–30 (the innermost
bracts grading into the chaffy bracts), narrowly lanceolate to lanceolate, the
outermost bracts occasionally narrowly ovate, spreading to reflexed above the
midpoint, green, the margins and outer surface roughened-hairy (glabrous
elsewhere), not glandular (rarely a few sessile, yellow glands present in E.
paradoxa), the midnerve inconspicuous. Receptacle strongly convex to
conical, usually elongating somewhat as the fruits mature (also broadening
somewhat as the fruits mature), with chaffy bracts subtending the ray and disc
florets, these concave and wrapped around the florets, the sharply pointed,
spinelike tips noticeably longer than the tips of the disc corollas, hardened
(somewhat softer and leathery in E. purpurea), the apical portion orange
to dark purple, persistent at fruiting. Ray florets 8–21, sterile (lacking
stamens and style at flowering and with an ovary that is shorter and thinner
than those of the disc florets, not developing into a fruit) or rarely a few
pistillate, the corolla showy, relatively slender, spreading to drooping at
flowering, pink, purple, or yellow, rarely white, not persistent at fruiting.
Disc florets numerous (more than 200), perfect, inconspicuous (because of the
overtopping chaffy bracts), the corolla pink, purple, yellow, or occasionally
green, slightly bulbous-thickened at the base, not persistent at fruiting (but
sometimes trapped by the subtending bract). Style branches with the sterile tip
somewhat elongate and tapered. Pappus of the disc florets of a low rim or crown
similar in color and texture to the fruit body, the margin slightly irregular
and sometimes with 2–4 triangular teeth (at the angles of the fruit),
persistent at fruiting. Fruits wedge-shaped in outline, slightly flattened and
usually somewhat 4-angled in cross-section (3-angled in rare fruits of ray
florets), more or less smooth, the surface glabrous (hairy elsewhere), tan to
nearly white, usually with an abrupt, brown to dark brown region toward the
tip, sometimes slightly shiny. About 9 species, U.S., Canada.
The rootstocks
of Echinacea species are commercially important as medicinals. Native
Americans used the plants to treat a variety of ailments ranging from
snakebites to toothaches, burns, arthritis, rheumatism, swollen glands, and
other pains (Moerman, 1998). McGregor (1968) discussed the more recent history
of medicinal use, beginning with Meyer’s Blood Purifier, a tonic prepared from E.
angustifolia by a Nebraska doctor named Meyer, who learned of the plant
from local North American Indians during the 1880s. Because medical science was
unable to substantiate the curative properties of the genus, the American
Medical Association discouraged the use of Echinacea, but its use in
homeopathic medicine flourished in Europe, particularly in Germany (Hobbs,
1989; Foster, 1991). Beginning in the 1940s, new research began to hint at
various antibacterial and antiviral properties of the root extract. Today the
plants are used to provide a nonspecific stimulant to the immune system, both
as a general tonic and to ward off colds and other illnesses, and Echinacea
extract can be found in many health-food shops and even grocery stores. Much of
the research on the efficacy of the plants continues to occur in Germany (Bauer
and Wagner, 1990), but clinical studies in the United States continue to offer
somewhat contradictory findings. All five of the species present in Missouri
have been utilized, but apparently E. pallida is the preferred species.
The
international market for Echinacea roots has led to intense demand for
wild-collected roots. In Missouri, the genus ranks among the most-collected by
so-called root-diggers (individuals who supplement their incomes by harvesting
a variety of natural products from local areas and selling these to
distributors). The gradual elimination of these beautiful wildflowers from mile
upon mile of the state’s roadsides was one of the main reasons for the
enactment of laws restricting the collecting of plants from public highways in
Missouri. Although much of the collection of rootstocks continues to take place
legally on private property with landowner permission, managers of public lands
such as state conservation areas and the state parks system have recorded
numerous instances of unscrupulous individuals who have vandalized high-quality
glades and prairies that were protected by state law for the preservation of
native ecosystems and their enjoyment by all Missourians. Perhaps in part
because of restrictions placed upon where Echinacea can be collected
legally, some wholesalers have reported counterfeit coneflower roots collected
from Parthenium species, which superficially resemble those of true Echinacea.
Species of Echinacea
also are cultivated as ornamentals. All of the species growing in Missouri are
available through wildflower nurseries to some extent, but only E. purpurea
(and its cultivars and hybrids) currently is sold more widely in the general
nursery trade. The fruiting heads also sometimes are used in dried flower
arrangements and other craft projects.