Reseda alba

Plants annual or biennial (perennial), 30-90 cm, glabrous. Stems erect, usually branched. Leaves (cauline shorter distally); blade ovate to ovate-oblong, pinnatisect (lobes 4-15 pairs, lanceolate-oblong), 3-15 × 3-5 cm, (base attenuate), margins entire or repand to raggedly toothed, surfaces glabrous. Racemes (dense) 20-40 cm; bracts persistent, lanceolate-linear, 3-3.5 mm. Pedicels 2-8 mm. Flowers: sepals persistent, 5(-6), not reflexed in fruit, lanceolate-linear, 2-2.5 mm; petals 5(-6), white, (3.5-)4-6 mm, subrounded-clawed, adaxial ones 3-lobed; stamens 10-14; filaments persistent, 2-3.5 mm, glabrous; intrastaminal nectary-discs papillose; anthers 1-2 mm; placenta entire. Capsules erect, 4-carpelled, cylindric to ovoid-oblong, 8-14 × 4-6 mm, apically 4-toothed, glabrous or ribs papillose. Seeds 1-1.3 mm, dull, finely papillose. 2n = 40.

Flowering May-Aug(-Nov). Muddy shores, dunes, waste places, railroad ballasts, roadsides, basic soils; 0-800 m; introduced; B.C., Man., Ont., Que., Sask.; Ark., Calif., Conn., Del., Ill., Kans., Maine, Mass., Mich., N.H., N.J., N.Y., Ohio, Oreg., Pa., Vt., Wash.; s Europe; sw Asia; n Africa; introduced also in South America, s Africa, Australia.

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.

Author: The Morton Arboretum

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.

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