the green bamboo, greenish bamboo
菉 refers specifically to a type of green bamboo, with the color green being an inherent part of its identity.
菉 combines the grass radical 艹 with 录, which likely contributes the sound. The character is used for a specific green bamboo, but the exact historical development is uncertain.
The grass top 艹 covers the lower part 录, which looks like a stylized bamboo shoot with water drops. Picture green bamboo growing under the grass.
For リョク, imagine a green bamboo grove that looks like a lush ryok (a made-up word for vibrant green): ryok -> リョク, and the bamboo is vividly green.