How does Selaginella move?

Perhaps people haven't discovered that the plants with the longest life span are not tall trees, but some perennial drought-resistant and barren weeds, such as cactus, which never dies after drought and takes root and sprouts. Among ferns, there is also a kind of nine-dead resurrection grass called Selaginella. Selaginella, who lives in the crevices of dry rocks, will roll into a ball and stop stretching when it encounters drought. When the rainy season comes, branches will roll out and continue to grow. In addition, Selaginella can "pull out" its roots from the soil without water, roll them into a ball and roll with the wind to find a place suitable for its growth. This kind of plant that can "move on its own" and "live in a nomadic way" is incomparable to other plants. Because Selaginella, rooting and other plants have these special abilities, it is difficult to calculate their life span or age clearly.