Comparative anatomy and chemical analysis of the vegetative organs of three species of Stigmaphyllon (Malpighiaceae)

• Vegetative organs of three species of Stigmaphyllon.
• The diffuse underground systems of three species of Stigmaphyllon.
• Chemical composition such as alkaloids, quinones, flavonoids and saponins.
• Several meaningful characters may aid further taxonomic studies of Stigmaphyllon.

The Brazilian Atlantic coast ‘restingas’ consist of enclaves of vegetation from northeast to southeast Brazil. This ecosystem on the eastern coast of Brazil is characterized by sandy dunes with shrubs and low forests further inland. Malpighiaceae is one of the most distinct families in such environments, with several species with economic and pharmacological importance. Despite this potential use, most studies focus on Byrsonima and Banisteriopsis. Stigmaphyllon comprises 90 species widely distributed in the Neotropical region. Nevertheless, studies with these species are scarce and focus on reproductive biology, floral morphology or taxonomical and phylogenetical approach. Thus, this paper presents novel insights regarding the anatomy, morphology and chemical composition of vegetative organs, especially the underground system, of Stigmaphyllon auriculatum, Stigmaphyllon ciliatum, and Stigmaphyllon paralias. For anatomical studies, we used botanical material fixed in a solution of paraformaldehyde and glutaraldehyde. Transverse sections of the vegetative organs were obtained from standardized samples of 3 individuals of each species. Extractions were performed separately on each species for detection of the main types of chemical compounds. We observed meaningful characters among the species, including the habit, leaf shape, the diffuse underground system, T-shaped trichomes, the shape and arrangement of the vascular tissues, among others. The chemical analysis revealed flavonoid, quinones, resins, quaternary alkaloids, free sterols and triterpenes, and condensate tannins in all species. Saponin were found only in S. ciliatum and S. paralias.