Family - Ranunculaceae

Stems - To 80cm tall, glabrous, hollow, branching above, thick below but easily broken, herbaceous, from fibrous roots, erect.

Leaves - Basal and lowest leaves on long petioles. Petioles to -20cm long, glabrous. Blades 3-lobed, to 8cm long, 6cm broad, glabrous. Lobes somewhat divided again, with rounded teeth. Upper leaves alternate, becoming sessile near apex of stem, typically 3-lobed, glabrous, +10cm broad, 8-9cm long.

Lower leaf.

Upper leaves.

Inflorescence - Single flowers on short or long peduncles terminating branches, often appearing axillary. Peduncles glabrous or with few sparse hairs, subtended by simple to lobed foliaceous bracts (uppermost leaves).

Flowers - Petals 5, yellow, shiny above, dull below, free, 3-4mm long, 2mm broad, broadly oblong to elliptic, glabrous, with cup-like nectary at base. Stamens +/-20, from base of pistils. Filaments to 2mm long, glabrous, pale yellow. Anthers yellow, .3mm long. Pistils in a cylindric head expanding in fruit to +2cm long, 1cm in diameter. Achenes glabrous, tuberculate, to 1.3mm long, slightly compressed, with minute beak. Sepals 4, ovate, reflexed to spreading, falling early, free, 2.5-3mm long, 2mm broad, pubescent externally, cupped, yellow-green.

Flowering - May - August.

Habitat - Streambanks, muddy shores, ditches, moist ground.

Origin - Native to U.S. and Eurasia.

Other info. - This is one of the first plants I photographed in this state. The plant is a fast growing annual which produces a multitude of small yellow flowers. The fruits are quite large for the size of the flowers and make the plant easy to identify.
Our plant belong to variety sceleratus f. sceleratus. There is another form which is aquatic and not yet found in this state. This is form natans Gluck.
This species can be found along the Missouri, Mississippi, and a few other rivers.
The plant is somewhat toxic and can cause skin irritation to people allergic to it.

Photographs taken in Parkville City Park, Parkville, MO., 6-10-00.