Sium suave (Water Parsnip) - photos and description

Sium suave

Sium suave

Sium suave

Sium suave

Sium suave

Sium suave
Linear bracts subtend the compound umbels

Sium suave

General: Tall perennial with an erect, branching growth habit. Plants glabrous.

Flowers: In compound umbels of white flowers. Umbels measured to 8 cm diameter, a single umbellet measured to 12 mm diameter. Single flowers have 5 petals, a flower measured at 3 mm diameter. Flowers fragrant. 5-10 bracts grow at base of umbels, deflexed, linear, measured at 12 mm long and 1 mm wide.

Leaves: Leaves alternate, reduced upwards, once-pinnate. Leaf highlighted in photo above was 33 cm long (including petiole) and 17 cm wide. Leaflets are sharply toothed, are stalkless, narrowly lanceolate, leaflet measured at 7 cm long by 1 cm wide.

Height: Height is listed in Budd's Flora to 200 cm, we measured plants to 144 cm tall.

Habitat: Sloughs and marshes.

Abundance: Common.

Origin: Native.

Similar species: This plant might be confused with the very poisonous Cicuta maculata (Water Hemlock), however that plant has leaves that are twice pinnate, while Sium suave has leaves that are once pinnate.

When and where photographed: Photos taken July 28th, in a marsh in mixed woods, Porcupine Hills, about 500 km north east of our home in Regina, SK.