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DescriptionThis introduced plant is usually a winter annual; less often, it is a summer annual or biennial. It overwinters as a low rosette of basal leaves up to 6" across. Individual basal leaves are up to 3" long and ¾" across; they are variably pinnatifid and hairless to mostly hairless. During the spring and early summer, this plant develops branching stems with alternate leaves. A robust specimen is about 1½' tall, 2' across, and rather bushy in appearance; however, specimens at barren sites are typically less branched and smaller in size. The stems are light green to reddish green and glabrous (or nearly so). The alternate leaves are up to 2½" long and ¼" across; they are medium green, linear to linear-oblong in shape, smooth or slightly dentate along their margins, glabrous, and sessile. Unlike the basal leaves, none (or very few) of the alternate leaves are pinnatifid. The upper stems terminate in elongated racemes that have abundant flower buds, flowers, and seedpods (silicles). These racemes eventually become about 3-4" long. The flower buds at the apex of each raceme are often slightly pink or red, particularly in bright sunlight. The greenish flowers are about 1/8" long and inconspicuous. Each of these flowers has 4 tiny white petals (or none), 4 linear green sepals, a pistil with a single style, and 2 or more stamens. The petals, if present, are smaller than the sepals. The slender pedicel of each flower is about ¼" long. The blooming period usually occurs from late spring to mid-summer, although some plants will bloom later in the year. Each flower is replaced by an orbicular 2-celled seedpod (or silicle) about 1/6" (4 mm.) long and across; this seedpod is flattened and it has a tiny notch at its apex. Each cell of this seedpod contains a single seed. The seedpods are light enough be blown about by the wind, thereby distributing the seeds. The root system consists of a taproot.