Family: Scrophulariaceae
Verbascum image
Robert R. Kowal  

Key to Wisconsin Verbascum

Author: John G. Zaborsky

    • 1a. Flowers one per bract; pedicels equaling or exceeding the bracts; midcauline stems and leaves glabrate or glabrous, the upper stem often glandular; basal leaves crenate-dentate or pinnately lobed V. blattaria

    • 1b.Flowers 2 or more per bract; pedicels shorter than the bracts; stems and leaves densely to sparsely tomentose (sometimes glabrate in V. nigrum), not glandular; basal leaves entire or shallowly crenate 2

    • 2a.Basal and proximal leaves with shallowly cordate to nearly truncate bases; leaf blades sparsely tomentose to glabrate; filaments with purple to violet hairs V. nigrum

    • 2b.Basal and proximal leaves with attenuate bases; leaf blades densely tomentose; filaments with yellowish to whitish hairs 3

    • 3a.Upper cauline leaves slightly, if at all, decurrent V. phlomoides

    • 3b.Upper cauline leaves decurrent 4

    • 4a. Corollas 3–5 cm wide; stigmas spatulate; anthers orange; upper leaves caudate V. densiflorum

    • 4b.Corollas 1.5–2 (–3) cm wide; stigmas capitate; anthers yellow; upper leaves acute leaves not caudate V. thaspus

All our species are introduced from Europe. The towering inflorescences of robust individuals are quite distinctive and easily spotted on the landscape.