This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
The exact historical development of 芇 is uncertain. It visually combines 艹 (grass) and 巾 (cloth), but the original meaning and component relationship are unclear.
With no clear meaning, picture grass 艹 growing over a piece of cloth 巾, as if nature is reclaiming something forgotten.
For ベン, imagine a bent piece of cloth under the grass: bent -> ベン, and the cloth is bent out of shape.