actinostele

A *protostele in which the central core of xylem is star shaped or somewhat lobed as viewed in transverse section. This type of stele is exhibited in various species of Psilotum and Lycopo-dium and in the roots of higher plants. Depending on the number of xylem lobes, usually between two and eight, the stele is described as diarch, triarch, etc., and polyarch if the number of lobes exceeds eight.