Sisymbrium altissimum

Family: Brassicaceae (A Utah Flora – Cruciferae) – Mustard Family

Annual herbs from taproots; stems 9.8” to 3.3' (2.5 to 10 dm) tall or more

Leaves: alternate, or basal and still alternate; most simple; lobed to entire, the lower ones usually pinnatifid; 0.4” to 8” (1 to 20 cm) long or more

Flowers: 4 yellow petals in the shape of a cross or crucifer; yellow petals 0.25” to 0.34” (6.3 to 8.5 mm) long, fading to white; 4 sepals; 6 stamens (with 2 outer shorter than the inner 4); 1 pistil; nectar glands commonly 4

Pollinators: insects; some self-fertile

Fruits: silique - a pod with 2 compartments with a thin partition

Blooms in Arches National Park: March, April, May, June

Habitat in Arches National Park: disturbed areas

Location seen: widespread, Visitor Center area, park road mile 0 to 2.5, Windows, Fiery Furnace parking lot

Other: The genus name, “Sisymbrium”, is an ancient Greek name for various plants of the mustard family. The species name, “altissimum”, means “tallest or highest”.

This is a non-native plant.

Many plants in this family are weeds and they flower early because they are annual. Many vegetables are in this family– radish, cabbage, cauliflower. A few species of plants in this family are poisonous to livestock.