Although superficially resembling palms, DNA studies have revealed that pandans are actually related to yams (Dioscoreaceae family) and other Old World tropical families, but not palms! Male and female flowers are on separate plants and lack petals or sepals, and flowers are so tightly clustered that it is hard to distinguish one from another. There is evidence that they diverged as a family about 51 mya. There are about 650 species of Pandanus worldwide, mainly restricted to tropical areas, and Australia has about 20–40 species (Kress & Sherwood, 2009, p. 86; Ramsey, 2008, pp. 136–7).