The gold links are from the Samboghakaya Realm, while the bright yellow lines are links that go directly to Dorje Chang Buddha. The first wave coming out of India are the green lines. As the Indian monks spread into South-east Asia you will see the bright Magenta link to the Theravada, the only remaining school of the Lineage of the Elders, the early or more traditional forms that gave us the Path of Renunciation. It was the Madhyamaka and Yogacharya branches representing the Profound and Method Lineages that provided the basis for the Mahayana or greater Vehicle. The Profound Lineage was the source of the Prajnaparamita or wisdom teachings that gave us the Path of Right View of Emptiness while the Method Lineage gave us the merit-building Path of Bodhichitta. This was what spread to China as shown by the red lines and from there to Vietnam (chartreuse lines), Korea (purple lines), and Japan (blue lines). Starting around the 7th-8th century the tantra or Vajrayana Vehicle was strong in India and that was what spread into Tibet and Mongolia (maroon lines). This is a gross over simplification of the migration and evolution of Buddhism. For example, there should be another gold line from Tsongkapa to Manjushri, as he was also able to receive guidance directly from the Samboghakaya realm as were others. We in America have almost all of these traditions.
Download the image below to see the Lineage tree of the Buddha School.