Another indication of plant maturity is the color of the pistils, the little hairs that grow from inside the calyxes. Their purpose is to collect male pollen to fertilize the ovum inside the calyx, creating a seed. When no male pollen exists calyxes grow dense without any seeds, resulting in sinsemilla cannabis. Near the end of the flowering phase, pistils change color, entering the window of peak maturity. The ratio of white pistils to red pistils determines the type of effects your plants are likely to produce: a high or stone. In the final few weeks of the flowering phase, the pistils change from bright white to a rusty orange or brown, signifying the end of the plant’s life cycle.