Matsya Purana — Cosmography of Jambūdvīpa: Varṣas
तत्रापि च महावृक्षो न्यग्रोधो रोहिणो महान् तस्यापि ते फलरसं पिबन्तो वर्तयन्ति हि //
tatrāpi ca mahāvṛkṣo nyagrodho rohiṇo mahān tasyāpi te phalarasaṃ pibanto vartayanti hi //
There too stands a great tree—a vast nyagrodha (banyan), the mighty Rohiṇa. They sustain themselves by drinking the juice of its fruits.
This verse is not directly about Pralaya; it belongs to a descriptive, cosmographic passage highlighting extraordinary regions where beings survive by the fruit-essence of a colossal banyan (Rohiṇa).
Indirectly, it models the Purāṇic ideal of simple sustenance and dependence on natural abundance—an ethical subtext that supports restraint and ecological stewardship, virtues encouraged for householders and rulers alike.
No explicit Vāstu or ritual procedure is stated; the significance is symbolic—great trees like the nyagrodha often function in Purāṇic thought as markers of sacred landscape and abundance rather than as building rules.