7. Liatris spicata (L.) Willd. (button snakeroot)

Pl. 270 e; Map 1127

Rootstock a more or less globose corm. Stems 40–150 cm long, glabrous (sometimes hairy elsewhere). Basal and adjacent lower stem leaves mostly short-petiolate, the blades 8–40 cm long, 3–12(–20) mm wide, linear or narrowly oblanceolate, the surfaces glabrous (occasionally sparsely hairy elsewhere), green, with 3 or 5 main veins, grading to the shorter stem leaves, these mostly sessile, 1.5–15.0 cm long, linear or very narrowly oblanceolate to very narrowly lanceolate. Inflorescences elongate spicate racemes, the heads densely or rarely more loosely spaced (the axis mostly not visible between heads), sessile or with stalks to 1 mm long, these with only 1 basal bract. Heads with 4–8(–14) disc florets, the terminal head not or only slightly larger than the others. Involucre 7–11 mm long, narrowly cup-shaped to nearly cylindrical, with 4 or 5 unequal, overlapping series of bracts (the outer series appearing progressively shorter). Involucral bracts ovate to narrowly oblong-ovate, rounded or broadly angled to a bluntly pointed, appressed tip, mostly with thin, pale to transparent margins, the margins or entire bract sometimes strongly purplish-tinged, entire or with few minute, irregular, hairlike processes, the main body appearing flat below the tip. Corollas 7–11 mm long, glabrous. Pappus bristles barbed. Fruits 4–6 mm long. 2n=20. July–October.

Uncommon, known thus far from a single site in Oregon County (eastern U.S. west to Wisconsin, Missouri, and Mississippi; Canada). Upland prairies.

Because this species is relatively widespread in cultivation, it may become recorded as an escape in other counties in Missouri at some point in the future. The Oregon County site for this eastern species was studied by Steyermark (1963) in the early 1930s. He found plants locally common in open, gravelly ground with upland prairie vegetation near the town of Bardley. In 1986, Tim Nigh of the Missouri Department of Conservation relocated this station. However, in the intervening decades, L. pycnostachya became common at the site and hybridized extensively with the original population of L. spicata, with the result that genetically pure L. spicata apparently no longer exists there. Plants of intermediate morphology apparently are referable to L. ×bebbiana Rydb. (Pl. 270 d) and are now the most abundant type there. Interestingly, another putative hybrid was collected by Bill Summers in 1986 in adjacent Howell County at a roadside station from which L. spicata has never been documented.

The Missouri specimens of true L. spicata are referable to var. spicata. A dwarf variant that grows along the southeastern Coastal Plain is known as var. resinosa (Nutt.) Gaiser.