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This adventive plant is a summer annual about 1-3' tall that is either sparingly branched or unbranched. The central stem is stout, round, light green, and more or less covered with white hairs; it also has fine longitudinal veins that are white. The alternate leaves are up to 6" long and 4" across (excluding the petioles), becoming smaller in the upper half of the central stem. They are cordate-ovate or elliptic and smooth or slightly undulate along the margins. The base of each leaf is rounded or wedge-shaped, while its tip is rounded and blunt. The lower surface of each leaf is usually pubescent, while the upper surface is less pubescent or hairless.  The central stem terminates in a stout panicle of spikes with whitish green flowers. This terminal inflorescence is up to 6" long (rarely longer in large plants). There are also shorter axilllary panicles of flowering spikes or simple spikes that develop from the axils of the middle to upper leaves. The flowering spikes are bristly in appearance from the crowded flowers and pointed bracts. Rough Pigweed is usually monoecious with separate pistillate (female) and staminate (male) flowers on the same plant. The pistillate flowers have 5 pale white sepals, an ovary with 3 styles, and no petals. The staminate flowers have 5 pale white sepals, 5 stamens, and no petals. The sepals are oblong and about 3 mm. in length; their tips are either short and pointed or flattened. At the base of each flower, there are one or more green bracts about 3-6 mm. long. These bracts have long pointed tips. The blooming period occurs from late summer to early fall and lasts about 1-2 months. Cross-pollination of the flowers is by wind. Each pistillate flower develops a single seed in a membranous bladder (utricle). This utricle splits up to release the seed. Each small seed is dark brown or black, flattened, and circular; it has a smooth and shiny surface. The root system consists of a short stout taproot that is usually tinted red. This plant spreads by reseeding itself. Cultivation


Creative Commons Attribution Non Commercial 3.0 (CC BY-NC 3.0)

© John Hilty

Source: Illinois Wildflowers


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