Pink family (Caryophyllaceae)
Description: This native annual plant is about ½2' 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. 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.
Cultivation: The preference is full sun and rather dry conditions. Poor gravelly or cindery soil is preferred, as this reduces competition from other plants. This plant can reseed itself readily, and is rather weedy.
Range & Habitat: Sleepy Catchfly occurs in most counties of Illinois and is widely distributed (see Distribution Map). It is occasional to common, depending on the area. Habitats include dry gravelly prairies, hill prairies, barrens, glades, rocky bluffs, pastures and abandoned fields, and areas along railroads and roadsides. It is more common in degraded, disturbed areas (particularly along railroads), but also occurs in higher quality habitats.
Faunal Associations: Primarily flies and small bees visit the flowers for nectar. Flies can become stuck to the sticky surface of the calyx (at least in some varieties of Sleepy Catchfly), while ants can become trapped in the sticky patches of the central stem. The plant is not able to utilize nutrients from these trapped insects, however.
Photographic Location: The photographs were taken near an abandoned railroad in Urbana, Illinois, on black cindery ground.
Comments: Sleepy Catchfly is a highly variable plant that is easily overlooked, except where it occurs in substantial colonies and happens to be in bloom. The plant in the photographs is the bicolored form of Sleepy Catchfly, Silene antirrhina bicolor, which is supposed to be uncommon. Plants that produce flowers without petals are referred to as Silene antirrhina apetala, while plants without sticky patches are referred to as Silene antirrhina deaneana. The plant in the upper photographs has the larger-sized flowers for Sleepy Catchfly, about 1/6" across. However, other forms with petals have flowers that span only 1/12" across. Sleepy Catchfly resembles some Stellaria spp. (Chickweeds) with grass-like leaves. However, Sleepy Catchfly has a much larger bladder-shaped calyx, as described above, and most varieties have sticky patches on the stem or calyx, which provides this species with its common name.