A Shrivelfig is a magical plant that originated in Abyssinia. When skinned, it is used as an ingredient in Shrinking Solution, just as the "shrivel" in the plant's name would seem to suggest.
History
1993
Pomona Sprout had second-year students prune Shrivelfigs with shears during a Herbology class in 1992. When Harry Potter went to dispose of some withered stalks that he had trimmed off his Shrivelfig, he ran into Ernie Macmillan, and afterward Ernie brought Hannah Abbott to work at the same plant as Harry and Ron Weasley.
Later in the same year, Severus Snape taught third-year Potions students to brew Shrinking Solution. Draco Malfoy claimed that his injured arm prevented him from tending to his own ingredients, so Snape ordered Harry Potter to peel the required Shrivelfig for Draco, a task which Harry did as quickly as possible.