20. Solidago rigida L. (stiff goldenrod, rigid goldenrod)
Oligoneuron
rigidum (L.) Small
Pl. 237 g, h;
Map 1009
Plants with the
rootstock short and branched, often producing short-creeping, stout rhizomes.
Stems 1 to several, 30–150 cm long, erect or ascending, with several fine,
longitudinal ridges or grooves, usually moderately to densely pubescent with
short, curved hairs, rarely sparsely hairy to glabrous toward the base or
nearly entirely glabrous below the inflorescence, not shiny. Leaves basally
disposed, often persistent at flowering (additional rosettes sometimes present
adjacent to the flowering stem). Basal and lowermost stem leaves with the blade
8–20 cm long, 1.8–4.0 cm wide, mostly 3–6 times as long as wide, oblanceolate
to elliptic-obovate, ovate, or oblong-elliptic, not or only slightly thickened
but often somewhat stiff, tapered to a long petiole at the base, angled to a
usually sharply pointed tip, the margins finely scalloped or minutely and
bluntly toothed, the surfaces moderately to densely pubescent with short, fine,
curved hairs (somewhat roughened to the touch), the undersurface with 1 main
vein, the pinnate secondary veins usually faint. Median and upper stem leaves 1.5–11.0
cm long, lanceolate to narrowly elliptic or elliptic, the margins of at least
the uppermost leaves usually entire, otherwise similar to the lower stem
leaves. Inflorescences terminal panicles, appearing flat-topped or less
commonly shallowly rounded in overall outline, the heads solitary or in small
clusters at the branch tips. Involucre 5–9 mm long, the bracts in 3–5 unequal
series. Involucral bracts mostly oblong and rounded to bluntly pointed at the
appressed-ascending tip, those of the outermost and rarely also innermost
series sometimes narrowly oblong and bluntly to sharply pointed at the tip, the
thin, white to yellowish white margins hairy, the outer surface glabrous or
finely hairy, with a green to pale green central region of varying width, the
midvein slightly thickened, the 1–3 pairs of additional veins usually easily
observed. Receptacle naked. Ray florets 6–14, the corollas 3.0–5.5 mm long,
yellow. Disc florets 15–35, the corollas 4.5–6.0 mm long, the lobes 0.6–1.1 mm
long, yellow. Pappus 3.0–5.5 mm long, most of the bristles slightly thickened
toward the tip. Fruits 0.8–1.7 mm long, obovoid, glabrous or sparsely hairy
toward the tip. 2n=18, 36. August–October.
Scattered nearly
throughout the state, but uncommon in the eastern portion of the Ozark Division
and apparently absent from the Mississippi Lowlands (eastern U.S. west to Montana,
Colorado, and Oklahoma;
Canada).
Bottomland prairies, upland prairies, loess hill prairies, savannas, glades,
openings of mesic to dry upland forests, and uncommonly banks of streams and
rivers; also old fields, pastures, railroads, roadsides, and open, disturbed
areas.
Stiff goldenrod
is an attractive species that is available for use in wildflower gardens at
some native plant nurseries. Steyermark (1963) noted that three varieties were
traditionally accepted across the range of S. rigida, but he was able to
locate Missouri
specimens to document only var. rigida. Heard and Semple (1988)
completed detailed morphometric studies on the species and also reported a
number of chromosome counts. They validated the three infraspecific taxa
accepted by earlier authors but chose to elevate them to subspecies status and
also refined the characters separating them. During their examination of more
than 1,800 herbarium specimens from throughout the range of S. rigida,
Heard and Semple discovered a small number of specimens to document native
occurrences of ssp. glabrata and ssp. humilis in Missouri.