A creature that sprouts from the earth on a stem, hatched from no egg and born from no mother: this is the Vegetable Lamb of Tartary, or Agnus scythicus, a half-plant half-animal that European naturalists seriously debated from the fourteenth century to the Enlightenment. Thom Sliwowski’s essay traces the myth from its first European appearance in The Travels of Sir John Mandeville (where it fruits as a gourd containing “a little beast, in flesh, in bone, and blood”) through a Renaissance who’s-who of skeptical inquiry — Cardano, Scaliger, Duret, Francis Bacon, Athanasius Kircher — who debated whether the creature could bleed without a heart, whether its wolf predator was plausible, and whether the “figure made the fable.” The turning point came when Sir Hans Sloane dissected a preserved specimen and found nothing but fern rhizomes “shap’d by Art to imitate a Lamb,” followed by Engelbert Kaempfer’s theory that the myth was a euphemism for the slaughtered fetal Karakul lambs whose pelts became astrakhan wool, and Henry Lee’s definitive 1887 case that the whole thing began as a garbled European reaction to cotton — “wool as white as that of a lamb grew on trees” became “lambs grew on certain trees.” The myth survives in Linnaeus’s taxonomy (Cibotium barometz, the fern species used to craft the fakes) and in Diderot’s encyclopedia, which deployed it as a case study in how to distinguish testimony from evidence.