The segetal weed communities of Cerdanya district (Catalan Pyrenees)

This paper deals with the study of the vegetation of segetal weeds (Secalietea Br.-B1. 1952) of Baixa Cerdanya district by means of the phytocoenological method and gives an overview about these communities in the extra-Mediterranean areas of Catalonia. Acidophilous wheatfield vegetation is referred to Scleranthetum annui, association belonging to Scleranthion annui Br.-B1. 1915, rare in the studied area. Concerning neutrophilous wheatfield vegetation, which belongs to Caucalidion lappulae, syntaxonomical treatements previously given to in Catalan Pyrenees and other areas of Iberian Peninsula are discussed. Three associations are recognized: Kickxio-Nigelletum gallicae Fanlo 1988, from Central Pyrenees; Violo-Legousietum hybridae O. Bolos 1959, spreading through Pre-Pyrenees and Central Catalonia; and Biforo radiantis-Centaureetum cyani Vigo, Carreras, Carrillo et I. Soriano, ass. nova, including the communities of Cerdanya district.