Stem Submerged Dicot: Nymphaea - Cross Section: Nymphaea Stem Magnification: 100x The Bulk Of The Stem Consists Of Open Airy Aerenchyma With Numerous Large Air Chambers That Aide In Respiration And Buoyancy The Vascular Bundles Are Surrounded By A Starch Containing Endodermis In Which The Red Staining Casparian Strip May Occasionally Be Seen. A Pericycle Can Be Seen Beneath The Endodermis. Like My Hydrophytes, Xylem Tissues Are Reduced While Phloem Tissue Are Well Developed And, In Lager Bundles May Form In Two Distinct Patches. Photo