Merged polarised light images of cross-sections of the stems of the common, or soft, rush Juncus effusus (formerly Juncus communis) and common mare?檚 tail (Hippuris vulgaris). The outer zone is the rush with vascular tissue arranged around the perimeter of the stem. The central area is from the mare?檚 tail stem which, typically for an aquatic plant, has the vascular tissue located centrally.