。
I memorized many of Takuboku's poems.
Literal
I [topic-は] Takuboku [possessive-の] poem [possessive-の] many [object-を] memorized.
啄木 refers to 石川啄木 (Ishikawa Takuboku, 1886–1912), a famous Meiji-era tanka poet known for his short-form poems and his slim collection 悲しき玩具. の多く ('many of X'). 暗記する ('to memorize,' literally 'dark-record' = record in the darkness of the mind). A literary-inflected statement about reading habit.