地下茎

• 土(earth; soil; land)RADICAL
• 也(also; punctuation mark (archaic))PHONETIC

The wide earth (soil) is also where all things flourish and grow.

• 一(horizontal line; boundary)RADICAL
• 卜(stroke descending downward)ASSOCIATIVE

A vertical stroke pointing downward across a boundary line marks 'below'.

• 艹(grass; plant)RADICAL
• 茎(stem reading reference)PHONETIC

A plant's stem (茎) is the part of vegetation that stretches vertically upward from root to leaf.