Matsyapurana 169.16

169.16

etasmātkāraṇāttajjñaiḥ purāṇaiḥ paramarṣibhiḥ
yājñikairvedadṛṣṭāntair yajñe padmavidhiḥ smṛtaḥ //

Round the lotus-shaped earth exist four oceans on the four sides. By the mere contemplation of Nârâyaṇa this lotus-shaped earth appears in existence So this springing up of the earth is termed Puṣkara Consequently lotus is called Puṣkara and for the same reason the high seers have enjoined the use of drawing the lotus before the performance of any sacrifice.—14-16