Biological Flora of the British Isles: Mercurialis perennis L.

Abstract

Summary1. This account reviews information on all aspects of the biology of Mercurialis perennis 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 disease, history and conservation. 2. Mercurialis perennis is a dioecious, clonal, perennial forb of woodland, hedgerows, limestone pavement, screes and tall-herb communities. It is very tolerant of low light; it can also grow in unshaded conditions, although higher light flux densities result in lower shoot biomass. It is Eurocaucasic, occurring throughout temperate areas of Europe as far east as the Russian border. 3. Mercurialis perennis occurs on a wide variety of soil types over a pH range from 4.3 to 8.5, although it is most abundant on more base-rich clay or loam soils with a low organic content. It seldom occurs on peat or very sandy soils. It can grow in soils with low availability of macronutrients but it responds positively to nutrient addition from atmospheric or agricultural sources. It is intolerant of waterlogging, mainly because of poor aerenchyma development; its limited capacity to oxygenate the root environment can lead to ferrous ion toxicity. The resulting superficial root development on heavy soils may confer drought susceptibility in summer. 4. Mercurialis perennis is predominantly wind-pollinated. Ants are the main dispersal agents and the seed bears an elaiosome which offers them a lipid-rich reward. Establishment from seed is uncommon and vegetative propagation is the main means of expansion, often leading to dense clonal stands of aerial shoots. 5. Mercurialis perennis has been described as a stress-tolerant competitor. The persistence of its clones and slow dispersal have led to it being regarded an as indicator of ancient, semi-natural woodland.

Patterns of sex ratio variation and genetic diversity in the dioecious forest perennial Mercurialis perennis

“…Mercurialis perennis usually forms discrete male and female clones (Mukerji 1936;Wade et al 1981;Jefferson 2008) that vary in size but often span one up to several meters in diameter and can consist of hundreds to thousands of flowering male or female ramets (Vandepitte et al 2009b). Local sex ratios vary, but male-biased patches are prevalent (Mukerji 1936;Wade et al 1981).…”

“…The species is windpollinated and females produce 2-20 seeds. Seeds are relatively large and weigh 4-10 mg (Jefferson 2008).…”

Land-use history affects understorey plant species distributions in a large temperate-forest complex, Denmark

“…Annual precipitation is 600 mm and average January and July temperatures are -0.1 and 16.5°C, respectively (Laursen et al 1999). The landscape is rather flat (maximum 30 m above sea-level), and soils are a mosaic of late-glacial moraine clay and moraine sand and 19th century alluvial sediments (Rasmussen 1966;Høy and Dahl 2000). The forest complex consists of nine more or less contiguous forests and is a mosaic of managed Fagus sylvaticaor, less commonly, Quercus robur-dominated forest, Alnus glutinosa-dominated swamps, mixed forests, part of which are left relatively unmanaged, conifer plantations and open bogs.…”

Ideas and perspectives: on the emission of amines from terrestrial vegetation in the context of new atmospheric particle formation

“…Crataegus monogyna flowers at the end of April and May (Gyan and Woodell, 1987). Mercurialis perennis (wind-pollinated, but with high foliage MA content) can emerge already by January, and females remain aboveground until the first frost in autumn (Jefferson, 2008). These examples illustrate that even just a handful of species could in principle cover extended periods and areas of MA emissions.…”

“…Crataegus monogyna commonly grows in Europe and from northern Africa to the Himalaya (Christensen, 1992). Mercurialis perennis grows in many European regions from Norway to the Mediterranean, as well as in northern Africa and the Caucasus from Iran to Russia, and it has been introduced to Australia (Jefferson, 2008). Crataegus monogyna flowers at the end of April and May (Gyan and Woodell, 1987).…”