is a genus of bushy, tuberous, herbaceous perennial plants native to Mexico. A member of the Asteraceae (or Compositae), dicotyledonousplants, related species include the sunflower, daisy, chrysanthemum, and zinnia. There are 42 species of dahlia, with hybrids commonly grown as garden plants. This great variety results from dahlias being octoploids—that is, they have eight sets of homologous chromosomes, whereas most plants have only two. In addition, dahlias also contain many transposons—genetic pieces that move from place to place upon an allele—which contributes to their manifesting such great diversity.