It came over from Europe - the bladder campion - and seeded itself abundantly along the roadsides. There, in Illinois as in England, the campion late in the afternoon opens its five, deeply cleft petals above the inflated calyx, and blooms in the twilight. Around them hum pale night moths which, in their nocturnal Sittings, very likely transfer pollen from flower to flower.
Silene cucubalus Wibel.
June - August Roadsides.
By morning the shining white flowers have turned pale pink and are drooped. The inflated bladder calyx becomes an even more inflated bladder seed-pod and distinguishes this campion from others in the family.
It is a plant which hastily appeal's in newly opened land. When a lane is put through a woodland, one of the first plants to spring up is the bladder campion. Perhaps it comes as seeds in bay, or they were stuck in mud on wheels - somehow the campion gets there. While it stays along the roads it is not an objectionable weed, but it may cause some difficulties in crop fields, especially the grains, where its seeds need to be sifted from the edible grains before they can be milled.
The bladder campion blooms all summer long. The stems are thin and pale, the leaves opposite and tapered, dark green and finely downy or fine-hairy. The five-parted flowers with protruding stamens and pistil grow in loose clusters at the tips of the stems and new buds often continue to appear from the axils of the leaves.