This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
The exact historical development of 蓜 is uncertain. It visually combines the grass radical 艹 with 配, but the original semantic and phonetic roles are unclear.
The top grass radical 艹 and the bottom 配 (distribute) might suggest distributing grass or plants, but the actual meaning is unclear.
For ハイ, imagine a high (ハイ) pile of grass under which something is distributed: high -> ハイ.
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