Stem cross-sections A CaOx (white arrows) in the hypodermis with birefringence filter B detail of A C sudan III–IV positive cuticle positive D sudan III–IV positive lipid droplets in the primary phloem E calcofluor positive (blue fluorescence) hypodermis cell walls F cortex and phloem cells walls staining positively withcalcofluor (blue fluorescence) G xylem vessels of both cortical and medullary bundles resulted positive to phloroglucinol H Detail of G.