Royal catchfly is a member of the Pink family (Caryophyllaceae). Stems are usually unbranched below the flowers and grow up to 4 feet tall, and are usually somewhat clammy-hairy. Plants typically have 10 to 20 pairs of opposite leaves along the stem, slightly pointed at the tip. Flowers are on individual stalks on the upper part of the plant. Each flower has a 1 inch long, tubular, 5 toothed calyx covered with sticky hairs, 5 bright red petals with scalelike flaps near the base and often with ragged tips, and 10 protruding pale stamens. It is a taprooted perennial.
Royal catchfly blooms late spring to fall, usually in July. It is found in prairies and open woods from southeastern Kansas and southern Missouri to Ohio, and north to northern parts of Illinois and Indiana.