A word appearing as ᴱQ. qinqenna in the Qenya Lexicon of the 1910s for “Solomon’s seal”, apparently an elaboration of ᴱQ. qinqa “drooping, languid” under the early root ᴱ√QIQI (QL/77). It likely refers to the drooping plant.

Neo-Quenya: Since I retain ᴺQ. quinqua “drooping” for purposes of Neo-Quenya, I’d retain ᴺQ. quinquenna as well.