Vegetarians in the Jewish community have searched for a suitable replacement for the zeroa (shankbone), one of the components of the seder plate. There have been a number of candidates, the most popular being the beet. Reprinted with permission of the author from www.davka.org.
Dr. Naomi G. Cohen of Haifa University reports (1997) that her husband’s family has been vegetarian for more than 70 years and that their seder plate contains two hard eggs. "The logic of this: the bone on the usual plate stands for the Korban Pesach [paschal sacrifice], and the egg for the Korban Hagigah [festival sacrifice], which was eaten before the little piece of the Korban Pesach in order to get one’s fill of food first. Well, if the Korban Hagigah can be symbolized by an egg, than why not the Korban Pesach as well?
This is an unusual and idiosyncratic solution.
Many vegetarians (those who use the Haggadot of Robert and Roberta Kalechofsky) use a combination of "dry" barley or wheat (wrapped in plastic wrap) along with olives and grapes. This second option comes with a modern midrash as its prooftext:
"As vegetarians, in place of the shankbone, we place olives, grapes, and grains of unfermented barley, which symbolize the commandments of compassion for the oppressed, to be found in the Bible. We use olives to commemorate the commandment to leave the second shaking of the olive trees for the poor, we use grapes to commemorate the commandment to leave the second shaking of the grapevines for the poor (Deuteronomy 24:20), and we use grains of unfermented barley (or other unleavened or unfermented grains), to commemorate the commandment not to muzzle the ox when it treads out the corn in the fields (Deuteronomy 25:4), in other words, to recognize the natural appetites of the animal and not interfere with them. This commandment is considered to be the oldest extant concept of ‘animal rights,’ and enshrines the dignity and rights of the animal."
— Haggadah for the Liberated Lamb (1985 [the next to last unnumbered page before the Seder begins], 1988) and Haggadah for the Vegetarian Family (1993).