It should be noted, however, that 'ki' at the end of 'Himoroki' differs in phonetics from 'ki' (tree) of Otsurui (second class) in ancient special Kana usage, so their origins have no relation with each other.
但し、末尾の「き」とは上代特殊仮名遣で乙類の「木」と音韻上違い、語源的には無関係である。