Coefficient of Conservatism:
Coefficient of Wetness:
Often in similar habitats to A. androsaemifolium, although more frequent on wet soils: shores, thickets, river banks, at least seasonally wet marshes and meadows; but also in disturbed ground, along railroads and highways, in fields.
Like A. androsaemifolium, variable especially in pubescence. Plants with leaf blades on the main stem ± tapered to distinct petioles are typical var. cannabinum. Plants with the main blades ± subcordate and sessile or nearly so are var. hypericifolium A. Gray [also known as A. sibiricum Jacq.] Plants with subcordate petiolate blades or otherwise intermediate between the alleged varieties support the skepticism with which they are now often viewed, but certainly more work is needed in this group. The mature corolla is usually about twice as long as the calyx, or shorter, and the flowers are ± erect in terminal cymes (at ends of main stem and principal branches), rarely axillary. The seeds (excluding hairs) in A. androsaemifolium do not exceed 3 mm in length, while in A. cannabinum they are distinctly longer, ca. (3.2–) 3.5–5.5 mm.