This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
蘼 combines the grass radical 艹 with 靡, which likely contributes sound. The exact historical development is uncertain.
The top is grass 艹, and the bottom is 靡, which can suggest spreading or waving. Picture a field of grass waving in the wind, but remember its meaning is uncertain.
For ビ, imagine a bee buzzing over the waving grass: bee -> ビ, and the bee hovers above the 蘼 plant.
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