18. Solidago radula Nutt. (rough goldenrod)

S. radula var. laeta (Greene) Fernald

S. radula var. stenolepis Fernald

Pl. 241 n–p; Map 1007

Plants with the rootstock short and somewhat thickened, often also producing branched short- to long-creeping rhizomes. Stems solitary or few to several, 40–120 cm long (but usually shorter than 100 cm), erect to loosely ascending, with several fine, longitudinal ridges or grooves, moderately to densely pubescent with short, stiff, mostly spreading hairs 0.1–0.6 mm long, these often broad-based (the stem roughened to the touch) and sometimes sparse 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 usually absent at flowering. Basal and lowermost stem leaves with the blade 3–10 cm long, 0.7–2.5 cm wide, mostly 4–6 times as long as wide, elliptic-lanceolate to elliptic or elliptic-oblanceolate, occasionally narrowly elliptic-obovate, somewhat thickened and relatively stiff, tapered gradually to a short to long, winged petiole at the base, angled or tapered to a sharply pointed tip, the margins sharply but finely toothed to shallowly scalloped or nearly entire and microscopically roughened to minutely hairy, the surfaces sparsely to moderately roughened with short, mostly spreading, broad-based hairs, the undersurface with 3 main veins, the lateral pair (and midvein) often somewhat raised, usually only slightly more prominent than the other pinnate secondary veins (these forming an irregular network), the veinlets often difficult to observe. Median and upper stem leaves 1–8 cm long, sessile or very short-petiolate, the blade mostly 2–6 times as long as wide, lanceolate to elliptic or narrowly elliptic-obovate, the margins of at least the uppermost leaves entire, otherwise similar to the lower stem leaves. Inflorescences dense, narrow to broad, more or less pyramidal panicles, the branches and often also the tip usually arched or nodding, the lowermost branches sometimes relatively long, the heads oriented upward along the branches. Involucre 3–5 mm long, the bracts in 3 or 4 unequal series. Involucral bracts oblong-ovate to narrowly oblong-lanceolate and mostly 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 often poorly differentiated, 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 4–8, the corollas 2.5–4.0 mm long, yellow. Disc florets 4–6, the corollas 2.5–3.0 mm long, the lobes 0.5–0.9 mm long, yellow. Pappus 2.5–3.0 mm long, a few of the bristles often slightly thickened toward the tip. Fruits 1.5–2.5 mm long, narrowly obovoid, finely hairy (sometimes only sparsely so). 2n=18, 36. May–October.

Scattered in the southern half of the state north locally to Monroe and Marion Counties, but absent from nearly all of the Mississippi Lowlands Division (southeastern U.S. west to Kansas and Texas). Openings of mesic to dry upland forests, ledges and tops of bluffs, glades, savannas, and rarely upland prairies; also roadsides.

Steyermark (1963) noted that this is one of the earliest goldenrods to start flowering in Missouri. He and some other authors attempted to segregate var. laeta and var. stenolepis from var. radula based on minor differences in involucral bract length and width, but these features overlap too much to make such recognition advisable.