title: Epilobium tetragonum
text: # Epilobium tetragonum
  
  Epilobium tetragonum, commonly known as the square stalked willow herb, is a species of flowering plant in the willowherb family Onagraceae.
  
  The erect perennial herb typically grows to a height of 0.1 to 1.3 metres (0.3 to 4.3 ft) and can have several stems. It blooms between January and November and produces pink-purple flowers.
  
  The species has become naturalised in the Perth and Peel regions of Western Australia.
  
  ## Appearance
  
  * Overhead view of small E. tetragonum plant
  * Diagram illustrating tetragonal / square arrangement of leaves
  
  Epilobium tetragonum is characterized by its distinctive square-shaped stem, with leaves evenly spaced in a tetragonal arrangement around the stem, giving the plant a square-like appearance. The leaves are hairless and solid green and have a unique shimmer in direct sunlight.
  
  