follicles of plants
蓇 refers specifically to plant follicles, the dry seed pods that split open along one side to release seeds.
蓇 combines the grass/plant radical 艹 with 骨, which likely provides the sound コツ. The character was created to name a specific botanical structure.
The grass radical 艹 sits above 骨 (bone). Imagine a plant whose seed pods are as hard and dry as bones—those are follicles.
For コツ, picture a plant follicle cracking open with a sharp 'kots!' sound, like a bone snapping: kots -> コツ.
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