and embedded in plastic resin(Historesin, Leica) according to manufacturer’s instructions. Sec-tions of 5 m were produced using a rotary microtome (LeicaRM2145) and fixed on slides. Sections were stained with Toluidineblue (O’brien et al., 1964) and alkaloid detection was performedwith Wagner’s (Furr and Mahberg, 1981) and Dragendorff (Svedsenand Verpoorte, 1983) reagents. Images were recorded using digi-tal photomicrographs (600 dpi) obtained with an Olympus BX51microscope.