Shiva Purana
केसराणि तदर्धानि शेषं चाष्टदलादिकम् ॥ द्विहस्तस्य तु पद्मस्य द्विगुणं कर्णिकादिकम् ॥ ८ ॥
The filaments shall be half that length. The remaining portion is occupied by the eight petals. If the width of the lotus is two hands, the measurements will be doubled.
english translation
kesarANi tadardhAni zeSaM cASTadalAdikam ॥ dvihastasya tu padmasya dviguNaM karNikAdikam ॥ 8 ॥
hk transliteration by Sanscript