Arrangement of whorls

Perianth arrangement describes the position of the sepal, petal or tepal members relative to one another around the floral axis. In a cyclic (whorled) arrangement, all the floral parts sit in clearly defined whorls or rings, as in Brassica and Solanum. In an acyclic (spiral) arrangement, the floral parts are instead arranged in a continuous spiral along an elongated, fleshy torus (receptacle), as in Magnolia. A spirocyclic (hemicyclic) arrangement mixes the two patterns, with some floral parts in wh …