The presence of an endothelium and scarce endosperm (ab initio) is common in species of Bignoniaceae, which are unitegmic and tenuinucellate (Souza et al., 2005 and Lohmann and Taylor, 2014). Pyrostegia venusta presents endosperm with two to six layers ( Gabrielli and Castro, 1995).
In the longitudinal section, the epidermal cells of the cotyledons are slightly tangentially elongated, in both the dorsal and ventral region (Fig. 10C). The mesophyll is parenchymatous with accumulation of alkaloids, lipophilic compounds such as fixed and volatile oils, as well as a scarce presence of starch. PAS-positive polysaccharides were identified on the cell walls and in the cytoplasm (Fig. 11A–D).