This native perennial plant is about 4-10' tall and remains unbranched, except for the panicle of flowering stems near the apex. The central stem is thick, hairless, and four-sided. The large opposite leaves are up to 8" long and 5" across, which join together around the central stem to form a cup that can hold water, hence the name of the plant. These leaves are broadly lanceolate to cordate, coarsely toothed, and have a rough, sandpapery texture. The yellow composite flowers bloom during early to mid-summer for about 1-1½ months. Each sunflower-like composite flower is about 3-4" across, consisting of numerous yellow disk florets that are surrounded by 18-40 yellow or pale yellow ray florets. The infertile disk florets protrude somewhat from the center and are rather conspicuous, while the ray florets are fertile. The latter produce thin achenes, each with a well-developed marginal wing, which are dispersed to some extent by the wind. The root system consists of a central taproot, and abundant shallow rhizomes that help to spread the plant vegetatively, often forming substantial colonies.