Douglas Ladd. USDA SCS. 1989.
Midwest wetland flora: Field office illustrated guide to plant species
. Midwest National Technical Center, Lincoln. Provided by USDA NRCS Wetland Science Institute (WSI).
Linnaeus, Sp. Pl. 2: 906. 1753.
50—300 cm (rhizomes often elongate, slender, plants colonial, roots fibrous).
green, blades broadly ovate to lanceolate, all but distalmost 1—2-pinnatifid or pinnately compound, leaflets/lobes 3—11, bases cuneate to attenuate or cordate, margins entire or dentate, apices acute to acuminate, faces glabrous or hairy (sometimes with translucent patches); basal (often withering before flowering) petiolate, 15—50 × 10—25 cm; cauline petiolate or sessile, mostly lobed to pinnatifid, sometimes not lobed, 8—40 × 3—20 cm.
(2—25) in loose, corymbiform arrays.
to 2 cm (8—15, ovate to lanceolate, margins mostly ciliate, glabrous or hairy).
hemispheric or ovoid to globose; paleae 3—7 mm, apices (at least of proximal) truncate or rounded, abaxial tips densely hairy.
8—12; laminae elliptic to oblanceolate, 15—50 × 4—14 mm, abaxially hairy.
9—30 × 10—23 mm.
150—300+; corollas yellow to yellowish green (lobes yellow), 3.5—5 mm; style branches 1—1.5 mm, apices acute to rounded.
coroniform or of 4 scales, to 1.5 mm.
Varieties 5 (5 in the flora): North America.
are grown as ornamentals. The cultivar 'golden-glow' is widely planted and occasionally escapes cultivation. Among the varieties traditionally recognized in floristic treatments, vars.
are the most distinctive. Detailed investigation may show that the other varieties, from eastern North America, represent broadly intergrading forms that should be subsumed under var.