FIG. 19-5. (cont.) Cross-sections of young roots showing A) diarch, B) tetrarch steles of fibrous roots, C) polyarch stele of a primary root through which water and nutrients are transported. (After White)
A) Diarch stele of fibrous root.
B.) Tetrarch stele of fibrous root considered to be usual.
C) Polyarch stele of large root.