Anethum graveolens L.
Family - Apiaceae
Habit - Annual forb.
Stem - Erect or ascending, to 1.7 m, glabrous, glaucous, longitudinally ridged, stout but hollow.
Leaf - Leaves alternate, glabrous, glaucous, petiolate, with base of petiole forming conspicuous and somewhat inflated sheath around stem. Blades to 35 cm, ovate, pinnately and multiply dissected into narrowly linear to threadlike segments, with ultimate segments to 2 cm long.
Leaf base and sheath.
Inflorescence - Terminal and axillary compound umbels, long-stalked. Involucre absent. Rays 10 to numerous, to 10 cm long. Involucel of a few narrowly linear bractlets or absent.
Involucel and ovaries.
Florets - On stalks 6-10 mm long. Sepals absent. Petals broadly ovate, blunt at tips, yellow. Ovaries glabrous.
Fruits - 4-6 mm long, narrowly ovate-elliptic, flattened dorsally, glabrous, brown, each mericarp with 5 thin ribs, narrowly winged
Flowering - June - August.
Habitat - Open, disturbed areas.
Origin - Native to Europe.
Other info. - This is the plant used to flavor dill pickles and many other pickled foods. The foliage is used extensively in Scandinavian cooking. The aroma of the plant is unmistakable and distinctive. This species is rarely found in the wild, only sporadically escaping cultivation. Escaped populations do not seem to persist long.
Photographs taken near Labadie, Franklin County, MO, 6-12-2017 and 6-26-2017 (SRTurner).