Biological Flora of the British Isles: Primula veris L

1. This account presents information on all aspects of the biology of Primula veris that are relevant to understanding its ecological characteristics and behaviour. The main topics are presented within the standard framework of the Biological Flora of the British Isles: distribution, habitat, communities, responses to biotic factors, responses to environment, structure and physiology, phenology, floral and seed characters, herbivores and diseases, history and conservation. 2. Primula veris is a distylous, perennial rosette hemicryptophyte, mostly found in well-drained, herb-rich meadows and grasslands, in scrub or woodland rides and edges, and on calcareous cliffs. It occurs on base-rich loams or clays, on limestone, and sometimes in dunes. 3. Native to the British Isles, it is characteristic of many mesotrophic and calcicolous lowland grassland communities, but it also extends into upland valleys in northern England and Scotland. In Ireland it is also native and most abundant in the central plain. Primula veris occurs throughout the temperate areas of Europe as far east as the Russian border. 4. Primula veris is a shade-intolerant species that shows reduced performance and flowering under shade or increased competition. The species is not able to penetrate anoxic soil layers and is therefore mostly absent from locations that are characterized by a high water table. It has a well-developed drought tolerance. 5. Primula veris is an obligate outbreeder which entirely depends on foraging insects for successful pollination. Although the species shows heterostyly, with two reciprocal morphs (pin and thrum), only relatively low levels of intermorph pollination have been reported. Seed dispersal is restricted to a few centimetres from maternal plants, whereas pollen flow is wider, but still limited to a few metres from parental plants. Both are factors that contribute to a significantly fine-scale spatial genetic structure and small neighbourhood size. 6. At several locations throughout the British Isles, P. veris occurs together with P. elatior and especially P. vulgaris. The hybrid P. veris x P. vulgaris = P. x polyantha occurs frequently in mixed populations, whereas the hybrid P. veris x P. elatior = P. x media has been rarely reported in Britain. 7. Although P. veris is still a widespread grassland herb, it is less abundant in the British Isles and continental Europe than before. This decline can be attributed to changes in land-use practices, such as the loss of traditional hay-meadow management, the loss of grazing and an increase of ploughing, in combination with ongoing destruction and nutrient enrichment of permanent grasslands. However, from 1980 onwards the species has increased substantially in many areas of the UK, largely because its seeds are included in wildflower seed-mixtures that are sown on new or upgraded road and motorway verges, embankments and urban conservation areas.