IUCN threat status:

Not evaluated

Comprehensive Description

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Description

This native perennial plant is 3-5' tall and unbranched, except near the inflorescence. The stout central stem is usually covered with stiff short hairs, but sometimes becomes glabrous with age. It is usually light green, but sometimes turns red in the presence of bright sunlight. The opposite leaves are up to 5" long and 2½" wide. They are broadly lanceolate to ovate, and have stiff small hairs on both the upper and lower sides, providing a sandpapery texture. The margins of these leaves are usually smooth, or they may have tiny teeth. As they ascend the stem, the opposite leaves rotate their direction by 90°. A panicle of composite yellow flowers appear at the top of the plant, resembling small sunflowers. Each flower is about 2–3" across, consisting of numerous disk florets surrounded by 12-25 ray florets. Only the ray florets are fertile. There is no noticeable floral scent. Often, there are side stems that bear smaller panicles of flowers. The blooming period occurs from mid-summer to fall, and lasts about 1-2 months. The seeds are large, flat, and lightweight – they can be carried several feet by the wind. The root system consists of a taproot and short rhizomes, which enable this plant to form clumps. Several varieties of this plant have been reported by various authorities, some of which may be natural hybrids with other Silphium spp.

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© John Hilty

Source: Illinois Wildflowers

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