Primroses and other primulas
The common primrose, Primula vulgaris, is one of 500 primula species thriving throughout the northern hemisphere. It can also be found in South America. Half of all these species are found in the Himalayas. Cowslips, polyanthus and primroses are all primulas but not all primulas are primroses. The flowering structure of primroses is different to that of cowslips and oxlips. Primroses have flowers that are produced singly on thin stalks (pedicels) directly from the centre of the plant. Cowslips and oxlips have a thick central stem which lifts the flowers above the ground. From the top of this, there are many flowers held on shorter pedicels. Cultivated, coloured primroses have the same habit as the wild primroses while polyanthus have a habit like cowslips and oxlips. Because these plants have been hybridised for centuries, plants occasionally produce flowers of both types. Deeper in hue and smaller in size, the cowslip, P. veris, is a plant of drier and sunnier sites. The flowers are held above the neat rosettes of leaves. The bell-shaped blooms are carried in lop-sided bunches. The oxlip, P. elatior, has pale yellow flowers in similar bunches. Where cowslips and primroses grow together, they hybridise and the false oxlip, P. x polyantha, may be produced. Superficially similar to the true oxlip, it can be distinguished by the flowers being held all around the trusses.