Charak Samhita
मूलं तु द्विविधं तस्याः श्यामं चारुणमेव च । तयोर्मुख्यतरं विद्धि मूलं यदरुणप्रभम् ॥७॥
[Types of Trivrita] Roots of the plant Trivrita are of two types. The one that is black (shyama) is more beneficial than the other blackish red one.
english translation