Dahlia L-yə, DAYL-yə) is a genus of bushy, tuberous, herbaceous perennial plants native to Mexico and Central America. As a member of the Asteraceae family of dicotyledonous plants, its relatives include the sunflower, daisy, chrysanthemum, and zinnia. There are 49 species of Dahlia, with hybrids commonly grown as garden plants. Flower forms are variable, with one head per stem; these can be as small as 5 cm diameter or up to 30 cm . This great variety results from garden dahlias being octoploids—that is, they have eight sets of homologous chromosomes. 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.