Pliny, in his Natural History , gives more details. In his description of oparine he says that it is a ramose, hairy plant with five or six leaves at regular intervals, arranged circularly around the branches. Patterns Regardless of the overwhelming multiformity of plants structure, there are common patterns that link a wide range of species. Those segments of parastichies which are visible, thanks to the contacts, are termed contact parastichies . The parastichies running in the same direction with respect to the axis of the plant with the same pitch constitute a family of parastichies , and two obvious families winding in opposite directions are called a parastichy pair .
Spirals winding direction Spirals winding doesn t have a strictly determined direction.
The numbers m and n in the parastichy pair on pineapples, cones, and sunflowers are consecutive Fibonacci numbers. The numbers of visible opposed parastichies rise along the Fibonacci sequence. The explanation of this phenomenon, called rising phyllotaxis, is the key for the understanding the origin of patterns in plants. Model Model is based on suitable analogy primordia with soap bubbles. The similar assumption has been made by a few authors, for instance, by Van der Linden.