Common burdock (Arctium minus): a common weed of nonarable land in Orestiada, Greece

Summary Common burdock (Arctium minus) is a common biennial weed of non-arable land in typical rural settings of Orestiada, Greece. The aim of this study was to describe the basic morphological traits of this species throughout the main phenological stages of its life cycle and to obtain some insight into its growth and productivity in Orestiada. Based on our observations, the plants occurred most commonly in moist and fertile soils, usually as isolated individuals or in small patches near the parent plants. The species is characterized by its large basal ‘elephant-ear’ leaves during the vegetative stage, appearing in alternate arrangement, with irregularly wavy and non-toothed edges, as well as with long hollow stalks forming a noticeable furrow on the top. By monitoring individual plants, it was found that fl owering (in the second year of growth) mostly occurred from late June up to early August. The fl owers were purple, occurring in bristly heads at the top of the stem. The bristly heads formed a fruit, containing small black seeds. The average number of capitula per plant, from randomly selected populations in Orestiada, was found to be 69.7 and 57.7 respectively, whereas the mean seed number per capitulum reached 30.3 and 33.3 seeds, respectively