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. Voucher Phylogenetic relationship**

Terpene synthases (TPS) are responsible for the terminal biosynthetic step of terpenoid production. They are encoded by a highly diverse gene family believed to evolve by tandem duplication in response to adaptive pressures. Taxa in the Myrtaceae family are renowned for their diversity of terpenoid-rich essential oils, and among them, the tribe Eucalypteae has the largest TPS gene family found in any plant (> 100 TPS). In this study, comparative analysis of Melaleuca alternifolia (tea tree), from the related tribe Melaleuceae, revealed some Myrtaceae have smaller TPS families, as a total of 58 putatively functional full-length TPS genes, and 21 pseudogenes were identified by manual annotation of a newly released long-read assembly of the genome. The TPS-a and TPS-b2 subfamilies that synthesise secondary compounds often mediating plant-environment interactions were more diminutive than those in eucalypts, probably reflecting key differences in the evolutionary histories of the two lineages. Of the putatively functional TPS-b1, 13 clustered into a region of around 400 kb on one scaffold. The organisation of these TPS suggested that tandem duplication was instrumental in the evolution and diversity of terpene chemistry in Melaleuca. Four TPS-b1 likely to catalyse the synthesis of the three monoterpenoid components that are used to classify tea tree chemotypes were encoded within a single small region of 87 kb in the larger cluster of TPS-b1, raising the possibility that coregulation and linkage may lead to their behaviour as a single locus, providing an explanation for the categorical inheritance of complex multiple-component chemotypes in the taxon.

A critical taxonomic and nomenclatural review of the Brazilian species of Acalypha (Euphorbiaceae, Acalyphoideae) is presented. As a result, 40 species (44 taxa including six subspecies) are accepted, 37 of them native (17 endemic) and three introduced; also, 132 names are considered synonyms, 28 of them for the first time. Two new combinations are proposed: Acalypha brasiliensis subsp. asterotricha and A. brasiliensis subsp. psilophylla, previously considered varieties of A. brasiliensis. Information about types is provided for all the valid names, and 54 lectotypes and one neotype are designated. Identification keys and detailed distribution maps of all the native taxa are also provided.