Late goldenrod , verge d’or haute

Plants 50–200 cm; rhizomes short- to long-creeping. Stems 1–40+, usually short-hairy throughout, sometimes proximally glabrescent. Leaves: basal 0; proximal cauline usually withering by flowering; sessile or subpetiolate, tapering to bases; blades oblanceolate, 95–150 × 16–20 mm, relatively thick and firm, entire to serrate along distal ¹ / 2 , strongly 3-nerved, apices acute to acuminate, abaxial faces finely strigose, more so along nerves, adaxial ± scabrous; mid to distal cauline blades oblanceolate (proximally) to lance-olate (distally), mid (30–)45–100(–170) × (5–)7–16(–25) mm, much reduced distally [(15–)25–55 × (3–)4.5–10(–17) mm], margins finely serrate (teeth 0–6(–14) per side on mid), distally usually becoming entire or remotely serrulate, adaxial faces ± scabrous, abaxial moderately strigillose, densely villoso-strigillose along nerves, distal sometimes minutely stipitate-glandular. Heads (15–)100–1200+, secund, in secund, pyramidal, paniculiform arrays, branches divergent and recurved, sometimes ascending-divergent, sometimes merely club-shaped thyrsiform in small plants, 5–30 × 2–25 cm (often 1.5–2 times as long as wide in southern plants). Peduncles 1–3.5 mm, moderately densely short hispiduloso-strigillose, sometimes minutely stipitate-glandular; bracteoles linear, sometimes minutely stipitate-glandular. Involucres narrowly campanulate, 2.5–4.5 mm. Phyllaries in ca. 3 series, strongly unequal; outer lanceolate, acute, inner linear-lanceolate, margins rarely minutely stipitate-glandular, apices acute to obtuse. Ray florets (5–)8–13(–17); laminae 0.7–1.5(–2) × 0.1–0.4(–0.5) mm. Disc florets (2–)3–6(–9); corollas usually 2.3–3.6 mm, lobes 0.5–0.9(–1.2) mm. Cypselae (narrowly obconic) 0.5–1.5 mm, sparsely to moderately strigillose; pappi 2.5–3.5 mm.

Solidago altissima has often been treated as S. canadensis var. scabra. The short hairs of the leaves can give fresh plants a gray-green tone not seen in S. canadensis var. canadensis. Numerous studies on S. altissima and its insect galls have been published by ecologists and entomologists (see W. G. Abrahamson and A. E. Weis 1997). Both subsp. altissima and subsp. gilvocanescens often have large insect galls (1–3 cm) on the mid to distal stems, unlike plants of S. canadensis and S. lepida. The species is divided here into two subspecies, at times difficult to distinguish: one eastern, one on the Great Plains.

Subspecies 2 (2 in the flora): c, e North America, Mexico; introduced worldwide.