The complete series is not found in nature, but many igneous rocks display portions of the series. The main limitations are the state of the liquid, the speed of cooling and the tendency of mineral crystals to settle under gravity:
If the liquid runs out of an element needed for a particular mineral, the series with that mineral gets interrupted.
If the magma cools faster than the reaction can proceed, early minerals can persist in partly resorbed form. That changes the evolution of the magma.
If crystals can rise or sink, they stop reacting with the liquid and pile up somewhere else.
All of these factors, like english on a bowling ball, affect the course of a magma's evolutionits differentiation. Bowen was confident that he could start with basalt magma, the most common type, and build any magma from the right combination of the three. But mechanisms that he discountedmagma mixing, assimilation of country rock and remelting of crustal rocksnot to mention the whole system of plate tectonics he did not foresee, are much more important than he thought. Today we know that not even the largest bodies of basaltic magma sit still long enough differentiate all the way to granite.