Hofmeister's rule states that in normal phyllotactic systems leaf primordia form as far as possible form each other. Sequentially formed primordia appear at positions farthest from all existing primordia. Here we apply Hofmeister's Rule to sepal initiation in several families of the Zingiberales. The flowers of the Zingiberales occur in cymose partial florescences. A cincinnus apex arises in the axil of a bract on a florescence axis. Following its initiation, the apex cuts off a prophyll (the secondary bract) while the apex forms the first flower of the cincinnus. This pattern of development continues with the production of a new cincinnus apex in the axil of the prophyll. This apex produces the prophyll and flower of the next higher order. Sepals are initiated in order following the general sequence specified by Hofmeister's Rule. In the first flower, the first sepal forms in the older part of the flower that is farthest away from the sites of meristematic activity. The older part of the flower is that which formed from tissue that was originally part of the cincinnus apex. If you imagine a clock with the first flower in the center of its face, the new cincinnus apex would be at three o-clock, and the first sepal would form at 10 o-clock. The second sepal now forms as far as possible from the first sepal, in the more mature, region of the flower. This places it at two o-clock. Finally the third sepal forms at six o-clock, the least mature region of the flower. In some species, there is a delay in the formation of the third sepal, most likely influenced by the immaturity of the side of the flower furthest from the florescence axis. Sepal initiation in the second and third flowers also follows Hofmeister's Rule.

Key words: developmental constraints, flower development, Hofmeister's Rule, inflorescence, phyllotaxy, Zingiberales