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,[1][2] is a clonal colony of a single male Quaking Aspen (Populus tremuloides) determined to be a single living organism by identical genetic markers[3] and one massive underground root system. The plant is estimated to weigh collectively 6,000,000 kg (6,600 short tons),[4] making it the heaviest known organism.[5] The root system of Pando, at an estimated 80,000 years old, is among the oldest known living organisms.[6] (…) in, Pando (tree), Wikipedia [link].