56. Liatris Gaertn. ex Schreb. (blazing star)
Plants
perennial, the rootstock an ovoid to depressed-globose corm, this usually
covered with the persistent, brown, fibrous remains of old leaf bases (except
in L. punctata, with an elongate rootstock). Stems solitary to several, erect
or ascending. Leaves alternate but sometimes so numerous and dense as to appear
indefinitely whorled, the basal and lower stem leaves short-petiolate, grading
abruptly into the sessile or very short-petiolate stem leaves; the basal leaves
often present at flowering, these and the adjacent lowermost stem leaves the
largest on the plant. Blades of the basal leaves usually oblanceolate to
narrowly elliptic, grading abruptly into the linear or less commonly narrowly
elliptic to narrowly oblong stem leaves, all tapered at the base, usually
tapered to a sharply pointed tip, the margins entire, the surfaces variously
short-hairy to glabrous or nearly so, often also gland-dotted, with 1 or 3(5)
main veins. Inflorescences unbranched terminal spikes or spikelike racemes
(sometimes somewhat branched elsewhere), sometimes leafy and the lowermost
heads then appearing axillary. Heads with 4–80 disc florets. Involucre
cylindrical to broadly cup-shaped or bell-shaped, the bracts mostly 18–40, in
usually 3 to several unequal, overlapping series, the bracts lanceolate to
broadly ovate, tapered (often abruptly so) to a sharply pointed tip, glabrous
or short-hairy, often also glandular. Receptacle flat or nearly so. Corollas
pink to purple, rarely white, often sparsely glandular on the outer surface,
sometimes hairy on the inner surface. Pappus of 12–40 bristles, these minutely
barbed (the short barbs mostly 0.1–0.3 mm long) or plumose (the feathery barbs
mostly 0.5–1.0 mm long). Fruits (8–)10-nerved or ribbed, slightly wedge-shaped
in profile (usually slightly and unevenly tapered at the base) to nearly
linear, usually minutely hairy and glandular, brown to dark brown. About 45
species, U.S., Canada, Mexico, Caribbean Islands.
Liatris species are among the showier plants to
grace native wildflower gardens. A number of species are in cultivation (Dress,
1959), and most of the Missouri taxa can be purchased at native plant specialty
nurseries in the state. Liatris spicata has become more widely available
at home supply centers and general plant nurseries and also is coming into
broader use as a cut flower at florists and even grocery stores. In the garden,
these plants attract a host of animals, including a wide variety of insects
visiting the flowers and birds feeding on the achenes, but the sweet, thickened
rootstocks are a magnet for voles and other herbivorous mammals. Rootstocks of
various species also were consumed raw or baked by early settlers and by Native
Americans. Various tribes also used some Liatris species medicinally as
a general analgesic, to settle upset stomachs, for urinary tract problems, and
in poultices to ease skin inflammations, among other uses (Moerman, 1998). The
common name snakeroot, applied to some species, apparently is in reference to a
belief in their efficacy in the treatment of snakebite. Horses sometimes were
fed a decoction of the rootstocks as a stimulant before races (Moerman, 1998).
Liatris is a taxonomically difficult genus that
requires much further research. For some of the complexes, species limits still
are not well understood, and the impact of hybridization and polyploidy upon
the recognition of species has not been well studied for most of our taxa. In
perhaps the only detailed study of hybridization in the group, Levin (1968)
examined a mixed population of L. aspera, L. cylindracea, L. ligulistylis
(probably actually L. scariosa), and L. spicata in northern
Illinois, documenting an extensive swarm of mostly fertile hybrids. Steyermark
(1963) noted that the last monographer of the genus, Lulu O. Gaiser (1946), did
not examine specimens from any of the herbaria having large holdings of
Missouri materials.