Root systems in plants are broadly classified as taproot systems and fibrous root systems.

In a fibrous root system, the primary (radicle-derived) root is short-lived and soon replaced by a large number of thin, thread-like adventitious roots that arise from the base of the stem. These roots spread in all directions near the soil surface and are roughly equal in size — there is no dominant main root.

Monocotyledonous plants (monocots) — such as wheat, rice, maize, and grasses — characteristically possess the fibrous root system. This is one of the key distinguishing features between monocots and dicots.

Dicotyledonous plants (dicots) typically have a taproot system, where the primary root persists and grows deep into the soil, giving rise to secondary and tertiary lateral roots.

Gymnosperms (conifers, cycads) also generally have taproot systems. Pteridophytes (ferns, horsetails) have adventitious roots but are not the group most specifically associated with this fibrous system description in standard classification.

Hence, the fibrous root system with short-lived primary root replaced by adventitious roots is a characteristic feature of Monocotyledonous plants.