In the first image, top left, is the Primrose group which includes Primula vulgaris, the common primrose which is early flowering.
The image centre is of the Candelabra varieties, P. beesiana which is a taller, later flowering Primula.
Illustrated top right P. denticulata which as its name suggests looks like a 'drumstick'. It is early flowering and a popular Primula to mix with spring bulbs.
P. candelabra are deciduous which means they die back in the winter, but they do return reliably each year for a great spring display and often flower into early summer. The polyanthus and primrose groups tend to be evergreen, or semi-evergreen.
Primula vulgaris, the common primrose looks lovely in a natural setting such as on a bankside, and it will multiple over time. Some varieties of Primula vulgaris are scented and shade tolerant. Whilst many Primulas are low growing the popular Candelabra beesiana will grow up to 60cms and the variety 'Harlow Carr' image below left is tall and has mixed tones of oranges and pinks
The name Polyanthus describes hybrids of P. vulgaris (Primrose) and P. veris (Cowslip) and these plants are often treated as bedding and discarded each year. Fact is, they are perennial and will come back the following year especially if planted in favourable conditions. To keep them going for a few years Polyanthus are best planted where there is good winter and spring light, because this is when they grow and flower. Polyanthus enjoy a degree of shade over the summer when they die back and then, they will hopefully re start in winter. Although Polyanthus are perennials and so potentially can live for many years, in reality most gardeners will persuade them into flower for only 3/4/5 years after which they may look a tad tired and have few flowers. The name Primula is derived from the Latin primis, meaning first and often Polyanthus are one of the first and very welcome flowers of spring.