Anatomy and histochemistry of Utricularia alpina tubers. (A, B) General tuber anatomy. Note the parenchymatous cortex (Pc), which surrounds the ectophloic central cylinder (CC). Scale bar = 100 µm. (C) Section after IKI treatment, showing positive reaction for protein in nuclei. Scale bar = 100 µm. (D) Reaction for lipids (Sudan IV). Scale bar = 100 µm.