Inflorescence architecture variability and its possible relationship to environment or age in a Mediterranean species, Euphorbia nicaeensis All. (Euphorbiaceae)

Euphorbia nicaeensis All. is a Mediterranean herbaceous perennial species t hat nourishes in different environments and successional stages. Sampled fr om a population in the Herault department (France), adult plants displayed three types of variation in the architecture of the inflorescence axes. The relative proportions of the three types in the different patches are more related to ecological conditions (density of vegetation cover, substrate, s uccessional stage of the patch) than to the age of individuals. Large diffe rences in flowering times and in the quantity of seeds produced between the three architectural types, within and between patches were observed. These differences, however slight, may be related to an intraspecific differenti ation tendency induced by the local environment heterogeneity. (C) 2001 The Linnean Society of London.