Seven species of annuals from western North America. They have pinnate to bipinnate leaves and often showy, bowl to cup-shaped, five-petalled flowers, sometimes with notched petal tips.
Although annuals, the best species have the right size and appearance to make them acceptable on the rock garden being ideal as fillers or to cover up areas of spring bulbs. Propagation by seed in situ ideally in autumn, as overwintered plants are bigger and bloom earlier over a longer period. Ordinary soil which is moist but well-drained and a sunny site are needed.