Field procedures and morphological aspects of the nectaries. (A) Floral nectary of a male flower of Cucurbita pepo (B) Application of 0.3 ml of 1% LYCH onto the accumulated floral nectar. (C) Flower immediately wrapped with aluminum foil to avoid sunlight. (D) Detail of the androecium. Note the pores of the nectary (arrows). (E) Transversal section of the nectary. Note the nectary tissues (arrow). (F, G) Extrafloral nectaries (EFN) in the petiole of Passiflora edulis Sims. (F) Nectar over the surface of the EFN (arrow). (G) Plant kept in the dark immediately after the application of a drop of LYCH over the nectar. Note the yellow aspect of the drop after the LYCH application (arrow).