Polarised light micrograph of a transverse section of the stem of Aristolochia trilobata. Aristolochia is a genus of evergreen and deciduous woody vines (lianas) and herbaceous perennials commonly known as birthwort, pipevine or Dutchman's pipe. A. trilobata, is an evergreen climber native to South America sometimes referred to as 'mil-homens'. It is an aromatic plant used to produce an essential oil used in the treatment of colic, diarrhoea and dysentery. It is also used in folk medicine to treat snakebite. Magnification: x28 at 10cm wide.