There are small triangular lobes at the top of the calyx. A flower is up to 1/6" across, while the calyx is about 1/3" long when fully mature. However, some varieties of Sleepy Catchfly have flowers without petals. When petals are present, they are white, pink, or purple, and sometimes bicolored (e.g., white on the upper side and purple on the lower side). The blooming period occurs from late spring to mid-summer, and lasts about a month. The flowers are diurnal, and open up in response to bright sunlight. There is no noticeable floral scent. The small seeds are distributed to some extent by the wind, as the slender stems sway back and forth readily. These seeds are kidney-shaped and have a bumpy surface. The root system consists of a branching taproot. Reproduction is entirely by seeds.
Sleepy Catchfly
Silene antirrhina
From Illinois Wildflowers
This native annual plant is about ½–2' tall and unbranched, except near the apex where the inflorescence occurs. The central stem is round, slender, and usually glabrous, although sometimes pubescent. There are usually sticky patches along the stem below the leaf nodes. The opposite leaves are up to 1½" long and 1/3" across. They are narrowly lanceolate, narrowly oblanceolate, or linear, with smooth margins, and are largely devoid of hairs, except near the base of each leaf along the stem. At the apex of the plant, is a loose cluster of flowers. A typical flower has 5 spreading petals that are notched at their tips, and a green calyx with 10 ridges that is ovoid in shape, hairless, and somewhat sticky.
