Shiva Purana
पद्मकल्पस्य माहात्म्यन्तत्र यस्यामुदाहृतम् ॥ तस्मात्पाद्मं समाख्यातं पुराणं च द्वितीयकम् ॥ १२६॥
The second Purāṇa is called Padma. It is so called because it mentions the greatness of the Padmakalpa.
english translation
padmakalpasya mAhAtmyantatra yasyAmudAhRtam ॥ tasmAtpAdmaM samAkhyAtaM purANaM ca dvitIyakam ॥ 126॥
hk transliteration by Sanscript