Which type of root system grows directly downward?

The taproot system is characterized by a primary root that grows directly downward into the soil, anchoring the plant and accessing deeper layers of moisture and nutrients. This type of root system typically has a single, thick central root from which smaller lateral roots may branch out. The deep penetration of the taproot allows plants to survive in periods of drought, as they can reach water sources that shallower-rooted plants cannot. Examples of plants with taproot systems include carrots, dandelions, and certain trees, such as oaks.

In contrast, a fibrous root system consists of many thin roots that spread out horizontally near the soil surface. This type of roots helps with stability and nutrient absorption from the top layer of soil but does not penetrate deeply. A surface root system remains primarily close to the surface of the ground, relying on the availability of moisture and nutrients in the top soil, while an adventitious root system develops roots from non-root tissues, such as stems or leaves, to help with support or nutrient uptake in various environments.