σεῖστρος
From LSJ
ἔνθα οὐκ ἔστι πόνος, οὐ λύπη, οὐ στεναγμός, ἀλλὰ ζωὴ ἀτελεύτητος → where there is no pain, no sorrow, no sighing, but life everlasting
English (LSJ)
ὁ,
A yellow-rattle, Rhinanthus major, growing in the Scamander, Arist.Mir.846a34, cf. Ps.-Plu.Fluv.13.2 (οίστρ- codd.).