Phyllotaxis is the study of the patterns on plants. The word itself comes from the Greek phullon, meaning "leaf," and taxis, meaning "arrangement." Phyllotaxis, in the restricted sense, is the study of the relative arrangement of what is called the primordia of plants. A primordium is, for example, what will become a leaf on a stem, a scale on a pinecone or on a pineapple fruit, a seed in the head (called the capitulum) of a sunflower, or a floret in the capitulum of a daisy. In other words, phyllotaxis is the study of the patterns made by similar parts (such as florets, scales, and seeds) on plants and in their buds. Anatomically, phyllotactic patterns are closely related to the vascular systems of plants, but phyllotaxis-like patterns are even present in the brown alga Fucus spiralis, in which there is no vascular system. The study of phyllotaxis has...