瓣
ベン, ヘン, わきま.える, わ.ける, はなびら, あらそ.う

petal, valve

JLPT0 G13 S0 F5000

As per 辡# as described in 弁 (split) + 瓜 pendent, oval-shaped melon/gourd → *petal* resembling a melon/gourd split into symmetrical halves → *seed* → *valve* (← resemblance of shape).

[Full Kanji Etymology List]