(b) : The examples of runners are doob grass, Oxalis, Centella etc. These plants have long and thin internodes and branches creep over the surface of soil. Such plants develop adventitious roots at nodes on lower side. When long branches breakup by any method they form new plants. Water hyacinth (Eichhornia) is the example of offset. This is sub aerial modification of stem. It is like runner but internodes are thick and short.