Xylem-2 

Aristolochia Flower in face view. This is called Dutchman's pipe because of its shape in side view. It has an interesting pollination biology.

Tracheary Elements have thick Secondary cell walls which are heavily Lignified. The specimen on the left is from the tropical vine Aristolochia. It has been stained with Toluidine Blue which stains Lignified walls Blue. The xylem is contained within the circle. Sclerenchyma in the Ground Tissue has stained positively for lignin in this slide.

Note the arrangement of Vascular Bundles in this low magnification image. This is typical for Dicots.

This specimen was stained with Phloroglucinol which stains lignin red.

This is the same specimen as above viewed with Polarized Light. The thick walls of the tracheary elements and Sclerenchyma in the Xylem are birefringent. Fibers in the Ground Tissue are also highly visible.