Photo – Venation network of young Populus tremuloides (quaking aspen) leaf (4X). By Benjamin Blonder, David Elliott (2011), University of Arizona, Department of Ecology & Evolutionary Biology, Tucson, Arizona, USA (link).
(…) Pando (Latin for “I spread“), also known as The Trembling Giant, is a clonal colony of a single male Quaking Aspen (Populus tremuloides) determined to be a single living organism by identical genetic markers and one massive underground root system. The plant is estimated to weigh collectively 6,000,000 kg (6,600 short tons), making it the heaviest known organism. The root system of Pando, at an estimated 80,000 years old, is among the oldest known living organisms. (…) in, Pando (tree), Wikipedia [link].