Annual or perennial herb to 0.8 m tall Stem: erect, coarse, branched above. Leaves: alternate, 5 - 10 cm long, pinnately and evenly divided into several linear-oblong segments. Flowers: borne in a long slender terminal infloresecence (raceme), greenish white, small, fragrant, with five or six sepals and five or six unequal petals, the uppermost petal largest and the others progressively smaller, each petal deeply three-lobed at tip. The stamens are borne ten to fifteen on a fleshy disk and are clustered on one side of the flower, and the ovary is four-lobed at the tip. Fruit: an elliptic capsule, 0.8 - 1.6 cm long, with persistent filaments and a four-lobed tip that opens at maturity, containing brown kidney-shaped seeds.
Similar species: Reseda luteola and Reseda odorata lack deeply divided leaves and have capsules that are nearly spherical. Reseda lutea has irregularly divided leaves, a three-lobed capsule, and greenish yellow flowers with twelve to twenty stamens, but lacks persistent filaments.
Flowering: June to October
Habitat and ecology: Introduced from Europe, this species is rare in the Chicago Region but grows in some waste places.
Occurence in the Chicago region: non-native
Etymology: Reseda comes from the Latin word resedo, meaning "to heal." Alba is the Latin word for white.
Erect, taprooted annual or perennial to 8 dm, glabrous and somewhat glaucous; lvs pinnately parted into several linear-oblong, evenly distributed, acute segments; fls greenish-white, fragrant; pet 5 or 6, commonly with 3 distinct or basally connate appendages, the central one the smallest; filaments persistent into fr; ovary and fr usually with 4 apical lobes; 2n=20. Waste places; Me. and O. to Del.; intr. from the Mediterranean region.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.