How did grasses evolve and how do they build themselves?

The Miracle of Cereal Growth. Every plant is a miracle of self-construction and it takes 100 trillion of these miracles to feed the world for one year. How does a cereal plant build itself? We have been following the process in barley by imaging the plant at different stages of growth using Optical Projection Tomography (similar to a CT scan but using light instead of X-rays). Within one week of sowing, the seed has grown into a seedling with a single visible leaf. By three weeks more leaves have been generated from a growth region (meristem) at base of the plant and floral buds have begun to form. At this stage what looks like the stem is really a series of wrapped leaf bases which protect the meristem at the base. Only after this does the true stem start to elongate, raising the developing flowers until they emerge from their leafy protection. By 4.5 weeks the flowers have formed and the stem continues to elongate. The flowers are fertilised inside the leaf protection and then set seed completing the life cycle before emerging.