The in orescences of Portulacaceae have traditionally been considered capitula and their morphology and architecture have not been studied in detail. The purpose of this study was to expand the knowledge on the in orescences within this family, comparing members of distinct lineages of Portulaca occurring in Brazil, to understand some systematic and evolutionary patterns within this group. Morphological characteristics of the in orescences were analyzed using a light stereomicroscope, and for anatomical studies, we made transversal and longitudinal sections along the entire in orescence, including involucral bracts, analyzing them using an optical microscope. We con rmed that observed in orescences are determinate, composed of a rst-order dichasium, with second-order helicoidal branches forming a cephalioid structure. The involucral leaves differed from adjacent bracts, which did not display a constriction at the base, as commonly observed in leaves. Thus, we conclude that the congested in orescence of Portulaca is not a capitulum, but a cephalioid with different degrees of branch reduction within the genus. The Pilosa clade displayed the most congested cephalioid compared to members of the other analyzed clades. We showed present to show a new interpretation of the congested in orescences in Portulacaand reinforce the need to analyze solitary in orescences to understand the importance of these data to systematics, evolution, and pollinator-plant interactions within Portulacaceae.
SpeciesVoucher Phylogenetic relationship**