13. Solidago nemoralis Aiton (old-field goldenrod, gray goldenrod)

Pl. 243 a, b; Map 1002

Plants with branched short- to moderately creeping rhizomes. Stems solitary or more commonly few to several, 20–100 cm long, erect or ascending, with several fine, longitudinal ridges or grooves, densely pubescent with minute, mostly curved hairs 0.1–0.3 mm long, not shiny, not glaucous, the upper nodes sometimes producing small clusters of leaves in the axils of the main leaves. Leaves basally disposed and persistent at flowering (additional rosettes usually present adjacent to the flowering stem). Basal and lowermost stem leaves with the blade 2–10 cm long, 0.7–2.0 cm wide, mostly 3–8 times as long as wide, nearly linear to narrowly oblanceolate, oblanceolate, or narrowly obovate, relatively thin or sometimes somewhat thickened, tapered gradually to a short to long, winged petiole at the base, rounded or angled to a bluntly or sharply pointed tip, the margins entire to finely scalloped or bluntly to sharply toothed, inconspicuously hairy, the surfaces densely pubescent with minute, mostly curved hairs 0.1–0.3 mm long, the undersurface usually with 1 main vein (a basal or median pair of secondary veins sometimes slightly more prominent toward the base than the others), the fine, pinnate secondary veins usually easily observed (these usually forming an irregular network). Median and upper stem leaves 0.8–6.0(–8.0) cm long, linear to narrowly oblanceolate or lanceolate, the margins mostly entire, otherwise similar to the lower stem leaves. Inflorescences dense, often narrowly pyramidal panicles (broadest near the base), the longer branches and tip usually somewhat arched or nodding, the heads oriented upward along the branches. Involucre 3–6 mm long, the bracts in 3–5 unequal series. Involucral bracts oblong-ovate to narrowly oblong-lanceolate and mostly rounded to bluntly pointed at the appressed-ascending tip (those of the outer series sometimes sharply pointed), the thin, white to yellowish white margins hairy (at least toward the tip), the outer surface glabrous, with a poorly differentiated, green to light green central region above the midpoint, this tapered gradually to the midvein, the midvein often slightly thickened and no additional veins present. Receptacle naked. Ray florets 5–9, the corollas 3.0–5.5 mm long, yellow. Disc florets 3–9, the corollas 2.5–4.5 mm long, the lobes 0.5–0.9 mm long, yellow. Pappus 2–4 mm long, a few of the bristles often slightly thickened toward the tip. Fruits 0.5–2.0 mm long, narrowly obovoid, sparsely to moderately finely hairy. 2n=18, 36. July–November.

Scattered nearly throughout the state (eastern U.S. west to Montana and New Mexico; Canada). Upland prairies, loess hill prairies, savannas, glades, ledges and tops of bluffs, openings of mesic to dry upland forests, and occasionally banks of streams and margins of ponds and fens; also old fields, pastures, railroads, roadsides, and open, disturbed areas.

Solidago nemoralis is a characteristic species of old fields and other open, grass-dominated habitats. Traditionally, most botanists have divided S. nemoralis into three or more infraspecific taxa. Brammall and Semple (1990) and Semple et al. (1990) performed detailed studies of cytological and morphometric variation across the range of the species, concluding that there were only two elements that could be separated consistently. These two subspecies are similar to the ones that Steyermark (1963) recognized as varieties, although Steyermark emphasized differences in leaf morphology, whereas Semple and his colleagues emphasized quantitative features of the heads, florets, and fruits that tend to correlate with ploidy level. Some Missouri specimens are difficult to determine below the species level, and there is some degree of morphological overlap between the two subspecies for every feature cited below.