Srimad-Bhagavatam: Canto 3 - Chapter 1 - Verse 36

Sanskrit:

तस्यैव चान्ते कल्पोऽभूद् यं पाद्ममभिचक्षते ।यद्धरेर्नाभिसरस आसील्लोकसरोरुहम् ॥ ३६ ॥

ITRANS:

tasyaiva cānte kalpo ’bhūdyaṁ pādmam abhicakṣateyad dharer nābhi-sarasaāsīl loka-saroruham

Translation:

The millennium which followed the first Brāhma millennium is known as the Pādma-kalpa because in that millennium the universal lotus flower grew out of the navel reservoir of water of the Personality of Godhead, Hari.

Purport:

The millennium following the Brāhma-kalpa is known as the Pādma-kalpa because the universal lotus grows in that millennium. The Pādma-kalpa is also called the Pitṛ-kalpa in certain Purāṇas.