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Pellucid punctuations and lines in the leaf blade are common in Casearia , but for some of its species these structures are mentioned as inconspicuous, not visible or obscure. Cavities and ducts have been anatomically described and correlated with pellucid punctuations and lines, respectively, in only six species from the genus; however, the distinction between these types of secretory structures remains unclear. Therefore, we aimed to anatomically describe the pellucid punctuations and lines in leaves of 47 species of Casearia . Leaf blade samples were obtained from herbarium and field collected material and processed according to standard methods for light microscopy analysis. Cavities and ducts were absent in only four of the 47 species ( C. commersoniana , C. javitensis and C. spruceana of section Piparea , and C. eicheleriana of section Casearia ). In the remaining species, cavities corresponded to pellucid punctuations, while ducts corresponded with lines. The majority of species have both structures randomly distributed throughout the leaf blade, however, in C. bahiensis , these structures are concentrated along the leaf margin, while in C. aquifolia and C. crassinervis they were predominant along the midrib. Our data show that anatomical analyses are essential for distinguishing between cavities and ducts. We also demonstrate that the distribution of cavities and ducts provides useful information for the taxonomy of Casearia at both the species and section levels. [ABSTRACT FROM AUTHOR]

• The leaf ontogenesis of Myrtoideae species revealed that the subepidermal layer is a hypodermis that originates from periclinal divisions of the ground meristem. • The occurrence of a hypodermis in representatives of Myrtaceae needs to be better studied and discussed in relation to the phylogeny of the family. • This study demonstrates the importance of ontogeny to understand plant structures so they can be properly used in taxonomic and phylogenetic interpretations. The ninth largest family of angiosperms is Myrtaceae, which comprises 127 genera and over 6000 species. The leaf anatomy of Myrtaceae has been widely studied and can be used in phylogenetic analyses and species delimitations in complexes within the family. A multiple epidermis and hypodermis have been described for the leaves of representatives of the family but have not been confirmed using ontogenetic studies, which could lead to incorrect interpretations about these tissues. Thus, we studied the leaf ontogenesis of the following 9 species in subfamily Myrtoideae: tribe Syzigieae - Syzigium cumini ; tribe Myrteae - Myrceugenia alpigena and M. euosma (subtribe Luminae), Psidium sartorianum, P. guajava, Campomanesia adamantium and Pimenta pseudocaryophyllus (subtribe Pimentinae), Myrcianthes pungens and M. gigantea (subtribe Eugeniinae). Shoot apices and leaves up to the fourth node were transversally and longitudinally sectioned following techniques used for plant anatomy. Leaf development in all species is from apical, intercalary, dorsal, marginal and plate meristematic activity. Protodermal periclinal divisions only occur to give rise to secretory cavities. The results show that in all the species the subepidermal layer is a hypodermis, which originates from periclinal divisions of the ground meristem. The occurrence of this layer could have phylogenetic implications according to reports in the literature, reinforcing the relationships among the subtribes in current topologies of Myrteae. However, the occurrence of a hypodermis in representatives of other subtribes of Myrteae and Syzigieae need to be better studied and discussed in relation to the phylogeny of Myrtaceae. [ABSTRACT FROM AUTHOR]

• The pericarp anatomy of Eugeniinae species revealed Myrcianthes pungens (which is in the genus sister to Eugenia) has a drupe-like fruit. • In species of Eugeniinae, the dorsal and ventral meristems in the ovary wall give rise to a mesocarp with three distinct regions. • This work supports the importance of ontogenic studies to appropriately delimit pericarp layers and may help reveal patterns in the pericarp structure that can contribute to estimating phylogenetic relationships. The genus Eugenia is of great ecological importance and due to being very diverse has been the subject of a comprehensive phylogenetic and taxonomic review to create an accurate classification. This study sought to describe the pericarp ontogeny of species in the subtribe Eugeniinae to reveal anatomical features that can be used to characterize morphologically similar sections. Buds, flowers, and fruits were collected at different development stages from herbarium specimens and plants in the field. Herbarium material underwent a reversal procedure, and fresh material was submitted to conventional anatomical analysis techniques and evaluated under an optical light microscope. By analyzing the species, we verified some promising characteristics, such as the following: a drupe-like fruit in Myrcianthes pungens (which is in the genus sister to Eugenia) that is a novelty for this species; trichomes in the inner epidermis of the ovary in species in Eugenia sect. Hexachlamys and E. sect. Pilothecium ; and the absence of intercellular spaces in the most internal layers of the mesocarp in a species of E. section Speciosae. Representatives from the subtribe showed predominant cell division in the layers subjacent to the exocarp (dorsal meristem) and endocarp (ventral meristem) and the outer, middle and inner mesocarp. [ABSTRACT FROM AUTHOR]

• Pericarp development in Campomanesia Ruiz & Pav. (Myrtaceae) species with a systematic point of view. • Results corroborate the literature for the genus delimitation. • Number of internal secretory cavities layers can distinguish species. • Presence of sclereids in ovary can distinguish species. • Presence of sclereids in fruit can be a characteristic to delimit the subtribe. Campomanesia (Myrtaceae) comprises approximately 45 species restricted to South America, 35 of which are found in Brazil. In this study, we ontogenetically analyzed species in the genus with the objectives of understanding and comparing the ovary and pericarp parts, highlighting characters that distinguish the species and providing information that could help to elucidate phylogenetic relationships in the future. We examined flower buds, flowers and fruits from herbarium specimens of 12 species. Results corroborate features that can be used as synapomorphies for the genus, such as the high number of locules, the development of one ovule per locule or the total sterilization of locules, and glandular locule wall. Campomanesia aurea, C. cavalcantina and C. xanthocarpa fruits have one or two layers of secretory cavities around the locules, whereas the remaining species have one layer. Sclereids were found in the ovarian mesophyll of C. guazumifolia, C. rufa and C. sessiliflora, while in the other species these only became evident when the pericarp was fully formed. The presence of trichomes and crystals was not consistent across species. Some anatomical characteristics, such as the disposition of secretory cavities in the outer and inner regions of the mesophyll and mesocarp, the presence or absence of sclereids, and the presence of trichomes and crystals at determined development phases, are promising to distinguish species in the genus. These features were compared with species in other closely related genera of Myrtaceae. [ABSTRACT FROM AUTHOR]