Flower:

Loose branching cluster of up to 15 stalked flowers at the top of the plant and arising from the upper leaf axils. Flowers are ¾ to 1 inch across with 5 white petals that are sometimes tinged yellow or pink, and are divided into 2 lobes. A short, ruffled appendage is attached to the petal at the mouth of the throat. 10 stamens and 3 styles are hidden inside the tube, the tips just visible at the mouth but not extending out of it.

The calyx is about ½ inch long at flowering time with 10 prominent veins and 5 long, narrow lobes at the tip. The calyx and flower stalks are densely covered in long, spreading, non-glandular hairs and short, sticky, glandular hairs.

Leaves and stems:

Leaves are toothless and densely hairy on both surfaces. Basal and lower stem leaves are 2 to 5 inches long, ¾ to 1¾ inches wide, generally spatula shaped with a short, winged stalked.

Middle and upper stem leaves are more lance-elliptic with pointed tips, becoming smaller and stalkless as they ascend the stem and reduced to bracts in the flower clusters. Stems are few-branched near the base, often branched in the upper plant, and densely covered in long, spreading hairs as well as sticky, glandular hairs in the upper plant.

Fruit:

Fruit is an egg-shaped capsule ½ to ¾ inch long that ripens to yellowish brown and splits open at the top, the 6 teeth strongly curved back. Inside are kidney-shaped seeds, dark brownish black with a gray bloom.

Notes:

Night-flowering Catchfly is often confused with another related weed, White Campion (Silene latifolia): both are glandular hairy and may be found in similar disturbed habitats. White Campion is best distinguished by having flowers that are either male or female, broader petal lobes, capsules with 10 teeth around the tip, and glandular hairs that are not sticky. By comparison, Night-flowering Catchfly has perfect flowers (both male and female parts), narrower petal lobes, capsules with 6 teeth, and sticky hairs. While both species bloom at night, Night-flowering Catchfly starts closing up in earlier morning where White Campion flowers may stay open until noon, or even later on cloudy days. We had been searching for Night-flowering Catchfly for some years without success, dissecting countless White Campion flowers looking for both stamens and pistils, all to no avail. It wasn't until we spotted a capsule with 6 teeth in the Whitewater Wildlife Management Area that we knew we had finally stumbled upon it. We collected the seed and grew it in our backyard garden to get the images you see on this page, then destroyed the plant. All in the name of science!