Just a few species of branching annuals, biennials, and perennials make up this genus of plants grown for their cross-shaped flowers and, sometimes, their translucent silver-dollar fruit. The casual habit of this old-fashioned plant makes it useful in a border, woodland, or cottage garden, where it will likely naturalize. For dried flower arrangements, cut the stems as the fruit loses its green color and hang upside down indoors in a cool place until dry.