Root Node

a large branch splitting off the trunk of a tree

ROOT NODE. Eucalyptus globulus, Tasmanian blue gum.
Streamside trail west of Stanford West Apartments.

A node of a binary phylogenetic tree is a point at which a branch splits into two. The root node of a rooted tree is the first point at which branches separate: the unique node from which all leaves descend.

Photo: Noah Rosenberg, October 7, 2016