Annual or perennial herbs with ascending to decumbent or erect stems (perennial usually with a woody rootstock). Leaves radical and cauline, of shape; radical leaves usually with a long attenuate base. Flowers solitary, in racemose or dichasia or paniculate cymes (see below). Calyx tubular, 5-toothed, (5-) 10-30-nerved. Petals with a distinct limb and claw; coronal scales present. Stamens 10, in 2 whorls. Styles 3-5. Ovary, stamen and petals borne on a carpophore (anthophore). Fruit a capsule, dehiscing by teeth, twice the number of styles. Seeds usually reniform, globose or subreniform, smooth or variously sculptured, back often grooved, sometimes winged or papillose.
The definition of the types of inflorescence in Silene is difficult but very important in the classification of the species. In the perennials the basic form of inflorescence is a 3-flowered cyme, with more or less equal pedicels, called dichasium (the lateral pedicels opposite). A compound dichasium is one in which the lateral branches in turn bear dichasia, so that a 5-7-many-flowered dicha shim is formed. A panicle is where the main axis terminates in a flower, the lateral branches (arising from main stern) bearing dichasia or 1-2-flowers. The solitary flower is considered to be derived from a dichasium by the suppression of its lateral branches. A monochasium is a derivative of the cyme in which the suppression of some branches results in a racemelike inflorescence.
Some species are gynodioecious. In these the hermaphrodite and functionally female flowers are borne on the same plant. The functionally female are usually smaller, with 5 small stamens, never exserted, and pale yellow anthers containing sterile pollen grains.