Microscopic features and chromatographic fingerprints of selected congolese medicinal plants: Aframomum alboviolaceum (Ridley) K. Schum, Annona senegalensis Pers. and Mondia whitei (Hook.f.) Skeels . ELSR. Published online February 14, 2018:1-10. doi:10.7324/ELSR.2018.410110