Wild mustard

Brassica kaber

Wild mustard is an annual plant that exhibits erect growth. The seedlings have broad kidney-shaped cotyledons (seed-leaves) that are indented at the tip. Older plants have alternate leaves that are somewhat hairy, especially on the lower surface of the veins. The lower leaves are usually stalked, deeply lobed with a large terminal segment and a few smaller lateral lobes. Upper leaves are stalkless, generally undivided but coarsely toothed. Plant height can range from 30-100 cm with either simple or much-branched stems. The stems usually have stiff downward pointing hairs, especially on the lower parts, and are green or somewhat purplish. Flowers are produced in small clusters at the ends of branches; these clusters elongating as the seedpods develop.

The flowers are bright yellow, about 1.5 cm across with 4 small sepals, 4 petals arranged in a cross formation, 4 long and 2 short stamens (total of 6), and 1 slender pistil. Flower stalks are thin and short (3-5 mm), becoming thicker but not longer as the seedpods develop. The seedpods, called "siliques," are 3-5 cm long, usually hairless, often with lengthwise ribs, erect and pressed to the stem or spreading out. Each pod has a flattened terminal beak about 1/3 the total length of the pod having 1 or 2 seeds in its base, and a main section containing several seeds that are released when the 2 sides or valves of the pod split apart from the bottom end and entirely fall away. Wild mustard can be confused with other annual yellow-flowered mustards.

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