Botany online 1996-2004. No further update, only historical document of botanical science!
Development of Recent Types of Steles in Pteridophytes and Seed Plants |
green: xylem, blue: phloem. Eustele, siphonostele (upper row), polystele (middle row)and aktinostele (lower row) are all derived from the protostele (according to W. ZIMMERMANN, 1959)