“…4) are represented in Europe and Asia and in both eastern and western North America, the latter as far north as Quebec. Because the largest and best-known genus Aristolochia, with up to 500 species, has often huge and bizarre flowers ( Hoehne, 1942), always apetalous, with a highly specialized, gamosepalous, usually bilaterally symmetrical, petaloid calyx, stamens adnate to the style to form a gynostemium, inferior, syncarpous ovary, and lianous habit with expectedly specialized stem anatomy, the family has rarely been included in the Annonales ( but see Wettstein, 1935). Often the family is treated as a separate order ( Cronquist, 1968;Takhtajan, 1966Takhtajan, , 1969 or allied with such improbable relatives as the parasitic Rafflesiaceae and Hydnoraceae and the tropical Nepenthaceae ( Melchior, 1964;Hutchinson, 1973).…”