उभयं कुष्ठगन्धि च । इति ॥ कZ_०२.११.६८ ॥
ubhayaṃ kuṣṭhagandhi ca | iti
Both (the foregoing varieties) also have an odour like kuṣṭha (costus); thus (the identification is stated).
Smell is a practical anti-adulteration test; defining it in the text standardizes enforcement and reduces revenue leakage from misgraded goods.