bamboo sheath, bamboo shoots
籜 centers on the protective outer covering of bamboo: the sheath that wraps young shoots. The meaning extends naturally to the shoots themselves, which are encased in these sheaths.
籜 combines 竹 (bamboo) with 擇, which likely contributes the sound. The character refers specifically to bamboo-related sheaths or shoots.
The top 竹 is bamboo, and the bottom 擇 looks like a hand selecting something. Picture a hand peeling away the bamboo sheath to reveal the tender shoot inside.
For タク, imagine a bamboo shoot tucked inside its sheath: tucked -> タク, and the shoot is hidden away.