European plants with C 4 photosynthesis: geographical and taxonomic distribution and relations to climate parameters

A survey of C 4 plants in Europe was performed with 216 species based on information in the literature and new studies. C 4 species were found in 10 families: the eudicots Amaranthaceae, Chenopodiaceae, Euphorbiaceae, Molluginaceae, Nyctaginaceae, Polygonaceae, Portulacaceae and Zygophyllaceae and the monocots Cyperaceae and Poaceae. The majority of the C 4 species belong to four families, Amaranthaceae (23), Chenopodiaceae (65), Cyperaceae (27) and Poaceae (88). In central and southern Europe, the abundance of native C 4 plants varied between 44 and 88% of total C 4 plants occurring, the rest being invasive C 4 species. The occurrence of total C 4 species, C 4 monocots and C 4 Chenopodiaceae was assessed for five major phyto‐geographical regions of Europe (north‐west, north‐east, central, south‐west, and south‐east). The abundance of C 4 plants of total C 4 dicots, C 4 Chenopodiaceae, total C 4 monocots, C 4 Poaceae and C 4 Cyperaceae was related to the climatic variables of annual mean daily temperature, annual precipitation and DeMartonne's aridity index. The abundance of total C 4 plants decreases with increasing temperature and expression of aridity (decreasing aridity index) and is not correlated with precipitation. The abundance of total C 4 dicots and C 4 Chenopodiaceae is correlated with precipitation and aridity but not temperature, whereas the abundance of total C 4 monocots, C 4 Poaceae and C 4 Cyperaceae is correlated with temperature and aridity but not precipitation. © 2010 The Linnean Society of London, Botanical Journal of the Linnean Society , 2010, 163 , 283–304.