Grasses recover quickly from bush fires in the savanna because of their

Grasses recover quickly from bushfires in the savanna because of their fibrous roots. Grasses have a root system that is made up of many thin, branching roots that spread out near the surface of the soil. These roots help grasses to quickly absorb nutrients and water after a fire. Fibrous roots also allow grasses to quickly send up new shoots from the base of the plant, even if the aboveground part of the plant has been burned away. This allows grasses to quickly recover and grow again after a fire. In contrast, succulent stems or perennating organs, which are options mentioned in the question, are not typically associated with the ability of grasses to recover after a fire.