Rhodora 2: 232. 1900.
Stems erect, to 100 cm, from rhizomes. Leaves: cauline leaves 3-4, those proximal to inflorescence petiolate, those subtending panicle branches sessile. Leaf-blade: leaflets reniform-cordate, apically 3-5-lobed, 15-50 mm wide, lobe margins crenate, surfaces glabrous to glandular. Inflorescences terminal, panicles, narrow with ascending branches, many flowered. Flowers: sepals yellowish to purple, oblong, 1.5-5 mm; filaments colored, not white; anthers 3-4.5 mm, mucronate; stigma purple. Achenes 4-13, erect, incurved, not reflexed, sessile; body fusiform to ovoid, not laterally compressed, adaxial surface 4-6 mm, glandular, veins prominent, not anastomosing-reticulate; beak (2-) 2.5-4 (-5) mm.
Phenology: Flowering early-mid summer (Jun–Jul).
Habitat: Alluvial or shingly calcareous shores and talus
Elevation: 0-200 m
N.B., Ont., P.E.I., Que., N.Y., Vt.
The relationship between Thalictrum confine and T. venulosum is unclear and requires additional field study.