Maror: Lettuce or Horseradish
Rabbi David Golinkin has a post about the identity of maror, Romaine Lettuce or Horseradish: Will the Real Maror Please Stand Up?
As Prof. Yehuda Feliks and many others have pointed out, there is no question that hazeret is Romaine lettuce (as opposed to iceberg lettuce). Rashi to Pesahim 39a calls it lituga which is leituge in medieval French. The Babylonian Talmud (ibid.) says that hazeret is hassa (lettuce) while the Yerushalmi says it is hassin (Pesahim 2:5, fol. 29c). The Yerushalmi asks how hazeret could be maror if hazeret is sweet? Rabbi Hiyya replies in the name of Rabbi Hoshaya: “Just as hazeret’s beginning is sweet and end is bitter, so did the Egyptians to our ancestors in Egypt.” So it is with Romaine lettuce – at the beginning it is sweet, but if you leave it in the field it becomes more and more bitter until it is inedible. The words hassa and hassin in Aramaic are equivalent to hassu in Akkadian, hassta in Syriac, and hash in Arabic.