Reference for Sukkah 63:8

ר' יהודה אומר: תניא ר' יהודה אומר משום ר' טרפון (ויקרא כג, מ) כפות תמרים כפות אם היה פרוד יכפתנו

If the central leaf is split, it is as though it is removed, and [the lulav] is invalid. R. Judah says It has been taught: R. Judah said in the name of R. Tarfon, “Branches (<i>kapot</i>) of palm-trees,” <i>kapot</i> [means that if palm-branches must be] were separated, he must tie them up (<i>yikhtefenu</i>).

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