21. Solidago rugosa Mill. (rough-leaved goldenrod, rough-stemmed goldenrod)

Pl. 240 a, b; Map 1010

Plants with branched, long-creeping rhizomes, often also thickened at the stem bases. Stems 1 to few, 30–150(–200) cm long, erect to loosely ascending, with several fine, longitudinal ridges or grooves, moderately to densely pubescent with short, mostly spreading hairs 0.1–1.2 mm long (sometimes less densely hairy toward the stem base), not shiny, not glaucous. Leaves chiefly cauline, the largest leaves about 1/3 of the way up the stem, the basal and lower stem leaves withered or absent at flowering (additional rosettes usually absent). Basal and lowermost stem leaves with the blade 6–12 cm long, 1–3 cm wide, mostly 3–8 times as long as wide, elliptic to lanceolate, sometimes relatively thick and stiff, angled to a sessile or occasionally very short-petiolate base, angled or tapered to a sharply pointed tip, the margins sharply toothed and inconspicuously hairy, the upper surface glabrous or sparsely to moderately roughened with short, stiff, broad-based hairs (sometimes only along the midvein) or occasionally with somewhat softer pubescence, the undersurface moderately to densely pubescent with spreading or curved hairs, with 1 main vein, the pinnate secondary veins sometimes strongly raised, easily observed (usually forming an irregular network). Median and upper stem leaves 1–12 cm long, ovate to elliptic or lanceolate, the margins toothed or those of the uppermost leaves entire, otherwise similar to the lower stem leaves. Inflorescences narrow to broad, open, more or less pyramidal panicles, the branches usually arched or nodding, the lowermost branches sometimes relatively long, the heads oriented upward along the branches. Involucre 2.5–4.5 mm long, the bracts in 3 or 4 unequal series. Involucral bracts lanceolate to narrowly oblong-lanceolate and bluntly to sharply pointed at the appressed-ascending tip, the thin, white to yellowish white margins hairy (at least toward the tip), the outer surface glabrous, with an elliptic or narrowly diamond-shaped, green to light green central region mostly above the midpoint, this tapered gradually to the midvein, the midvein often slightly thickened and keeled and no additional veins present. Receptacle naked. Ray florets 6–11, the corollas 1.5–3.0 mm long, yellow. Disc florets 3–8, the corollas 2–4 mm long, the lobes 0.7–1.2 mm long, yellow. Pappus 2.0–2.5 mm long, a few of the bristles often slightly thickened toward the tip. Fruits 0.9–1.5 mm long, narrowly obovoid, finely hairy. 2n=18, 36, 54. August–October.

Scattered mostly in the southeastern quarter of the state (eastern U.S. west to Wisconsin and Texas; Canada). Bottomland forests, banks of streams, rivers, and spring branches, fens, bases and ledges of bluffs, and less commonly mesic to dry upland forests; also pastures and roadsides.

Infraspecific variation in this is complex and poorly understood, and a number of subspecies and varieties have been named. There has not been any attempt to correlate the morphological features with the three ploidy levels recorded thus far. For further discussion see the treatments of the accepted varieties below.