What is a hilium in a seed?
small scar on seed coat, where seed was attached to parent plant.
The left hilum is higher than the right, due to the presence of the heart in the cardiac notch (in the left lung). 'The left hilium is situated slightly higher than the right pulmonary artery' (Miller 2006), and the hilium consists of the pulmonary artery, pulmonary veins and bronchioles. Reference: Miller W (2006) Diagnostic Thoracic Imaging. Chapter 14, p732