Description
This perennial plant is 3-12' tall. Plants in dense colonies are only 3-5' tall, but 'lone wolf' plants can achieve considerable height. The stout central stem is glabrous, glaucous, terete (circular in cross-section), and often reddish or reddish-purple in color. There is very little branching, except for some flowering stems that occur along the upper half of the plant. The leaves are up to 8" long and 2½" across, lanceolate-oblong, and either smooth (entire) or slightly to strongly serrate along their margins. The upper leaf surface is medium to dark green with a sandpapery texture that derives from the presence of minute stiff hairs. The lower leaf surface is pale green and softly hairy. The leaves are often slightly recurved, and they have a tendency to fold upward along their central veins, particularly during hot dry weather. The leaves are opposite below, but they become either alternate or opposite along the upper half of the plant. The leaves taper gradually into slender petioles that are about ½" in length. The upper stems terminate into either individual or small clusters of flowerheads. Each flowerhead is 2½-4" across, consisting of 10-20 ray florets that surround numerous disk florets. The tiny corollas of the disk florets are tubular-shaped and yellow, while the petaloid rays along the circumference of the flowerhead are bright yellow and oblong in shape. Around the base of each flowerhead, there are floral bracts (phyllaries) that are arranged in several overlapping series. These bracts are light green and linear-lanceolate in shape, becoming slightly recurved when the flowerhead blooms. On a large plant, it is not uncommon for several flowerheads to be bloom at the same time. The blooming period occurs from late summer to fall, lasting about 1-2 months. The disk florets are replaced by achenes about 3-4 mm. in length that are oblongoid and somewhat flattened in shape. The root system is fibrous and rhizomatous, often forming clonal colonies of variable size.
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Hilty, J. Editor. 2012. Illinois Wildflowers. World Wide Web electronic publication. flowervisitors.info, version 08/2012.
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