Photograph of a specimen of black primrose, ca.1920. Six blossoms are shown growing from the stalk below, which is riddled with small leaves. A neutral background can be seen behind.; "This is a large group of plants commonly known as the Primrose. They are mostly hardy perennial herbs and are natives of Europe and temperate Asia, Java and North America. Only one kind, P. magellanica, is found south of the Equator, in southern South America. Some Primroses, such as P. vulgaris, the English Primrose, bear their flowers singly on stems that rise straight from the base of the plant. Others, such as P. denticulata, P. obconica and P. elatior, produce their clusters of flowers in a head or umbel at the top of the flower stem. In another group, the flowers grow in an array of whorls spaced along the upper portions of the flower stems. Some Primroses can be grown in the rock garden, waterside or bog garden, some in the wild or woodland garden and others are suitable for growing in flowerbeds, greenhouses and gardens. The summers are too hot over most of the U.S. for growing many of the Primroses, but in the Pacific Northwest and other favorable areas many can be cultivated successfully. Only a few of the most tolerable plants can be grown in climates that are hot and dry. Hardy Primroses may be divided into two main categories: the bog or woodland kinds and the cliff and rock dwellers. There are also many Primroses that could be called meadow plants, because they grow best in the garden in beds of loam. Primroses that are grown in a greenhouse make gorgeous potted plants that bloom in late autumn, winter and early spring. The Chinese Primroses, which are varieties of P. sinensis, are favorites. There are two main types of Chinese Primroses, the large-flowered, which produce clusters of large flowers and the small-flowered or star (stellata) varieties, which grow tall and bear sprays of beautiful blossoms for many weeks in the winter and early spring. The small-flowered varieties are easier to grow than the Primroses with the larger flowers." -- unknown author.