Normally, only four internodes elongate. The roots, culm, and leaves make up the vegetative part of the plant. The floral part consists of the panicle, spikelets, and flower. Roots Shortly after seed germination, the fibrous root system of the rice plant begins to develop both outward and downward from the plant's base. The size and length of the roots vary.
Drained conditions are best for good root development that is proportionate to top growth.
Maximum root development is reached at the peak of the tillering stage, then begins to decrease, and toward the fruiting stage, almost ceases. Culm height varies according to management practices and varieties. Current United States varieties range from 30 to 46 inches high. Usually the top internode is the longest and bears the head. The leaf varies in length, form, and tightness, and covers the stem.