The complexity of plants, expressed in terms of Φm, includes a range of increasingly ordered structures for a wide variety of photosynthesizing life-forms at various stages of the biological-evolutionary phase of cosmic evolution. Note how flowering angiosperms have higher energy rate densities than gymnosperms or protists, and, in turn, more organized, cultivated C4 crops such as maize and sugarcane even higher values; yet all such plants on Earth have Φm values within a factor of ~20 of one another.
