Helianthus stem. Light micrograph (LM) of the stem of a perennial sunflower (Helianthus sp.) in cross-section showing the vascular bundles (green, yellow).Vascular tissues transport water and dissolved substances inside the plant and helps support the stem. The two types of vascular tissue are xylem and phloem. Xylem carries water and dissolved ions from the roots to stems and leaves. Phloem carries dissolved sugars from the leaves to all other parts of the plant. Xylem has two kinds of conducting cells, tracheids and vessel elements. Perennial sunflower is a crop of sunflowers that are developed by crossing wild perennial and domestic annual sunflower species. Magnification x 10 when printed 10cm wide.