Proc. Amer. Acad. Arts 17: 191. 1882.
Plants 30–210 cm; caudices branching, thick, woody. Stems 1–10+, ascending-erect, glabrous, often short fascicles of leaves present at nodes in axes of distal cauline leaves. Leaves: rosettes present at flowering; basal and proximal cauline tapering to elongate, winged petioles, bases nearly sheathing stems, blades linear-lanceolate, 50–260 (including petiole) × 5–45 mm, somewhat fleshy (fresh), margins entire, faces glabrous; mid and distal cauline crowded (robust plants), sessile, blades linear-lanceolate to lanceolate, 20–130 × 5–10 (–25) mm, reduced distally, margins entire, apices acute to attenuate, glabrous. Heads 70–320, usually not secund, in thyrsiform-paniculiform arrays, sometimes apically secund, 5–25 (–50) × 2–14 cm; branches ascending to arching. Peduncles 2–8 mm, glabrous or sparsely strigose; bracteoles 1–3, distally grading into phyllaries. Involucres campanulate, 2.5–4 mm. Phyllaries in 3–4 series, linear-triangular, unequal, margins involute near tip, sharply acute, the outer 1/3–2/3 length of inner (1–3 × 0.4–0.9 mm), midribs usually enlarged and translucent. Ray-florets 8–12; laminae 1–2.5 × 1 mm. Disc-florets 10–20; corollas 3–4 mm, lobes 1–1.5 mm. Cypselae (narrowly obconic) 2 mm (5–7 broad ribs lighter than body), sparsely to moderately strigose; pappi 2–3 mm. 2n = 18.
Phenology: Flowering Jul–Oct.
Habitat: Wet stream banks, springs, marshes
Elevation: 0–2500 m
Calif., Mexico (Baja California)
Solidago confinis is similar to S. spectabilis and was treated by A. Cronquist (1994) as a variety of that species.
"thick" is not a number.