Visualizing Hofmeister's Rules

Compare a scanning electron micrograph of a Norway spruce (Picea abies) shoot apical meristem with a computer generated arrangement of primordia. The computer program implemented the mathematical model based on Hofmeister's rules. Primordia are numbered according to their age---the higher the number, the older the primordium. Notice the remarkable similarity between plant and model.

Least Crowded Spot
Primordia form one at a time at regular time intervals. The newest primordium initiates at the periphery of the meristem where there is the largest space. Accordingly, the mathematical model places a new dot on the periphery of the meristem where it will be farthest from its neighbors.

Radial Displacement of Primordia
As they grow, older primordia are displaced radially away from the center of the circular meristem. The older the primordium, the farther it is from the center.