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Stachytarpheta (Verbenaceae) encompasses approximately 120 species distributed throughout tropical and subtropical regions of the Americas, with Brazil boasting the highest species richness (90 spp.) and endemism (82 spp.). This study introduces an updated, taxonomically revised, and credible occurrence dataset focusing on Stachytarpheta species in Brazil, comprising 4,843 records. This dataset results from expert revision of herbarium collections and integration with global repositories alongside national repositories in Brazil. It facilitates a thorough exploration of the temporal, geographical, and taxonomic patterns of Stachytarpheta across diverse regions and landscapes in Brazil. Stachytarpheta species and their occurrence records are concentrated in the states of Minas Gerais, Bahia, and Goiás, particularly in the campo rupestre and savanna formations of the Espinhaço Range and Chapada dos Veadeiros. Analysis of potential biases within our dataset revealed a correlation between specimen occurrences and proximity to roads. Rarefaction curves indicate ongoing potential for species discovery within the Cerrado and Caatinga domains, with the Tocantins state emerging as a particularly promising area for novel findings; therefore, presenting opportunities for exploration. The majority of the specimens are housed in Brazilian herbaria, particularly at RB, HUEFS, and CESJ. Temporal analysis of occurrence records showed an upward trend during the 20th century and the first decade of the 21st century, which can be attributed to the efforts of generalist collectors working mostly in Eastern and Central Brazil. Most collection efforts were carried out through Brazilian and European initiatives, often supported by local funding, especially during the mid-20th century. However, funding for scientific initiatives in Brazil has waned since the mid-2010s, potentially affecting recent trends in species recording. Our dataset serves as a resource enabling subsequent analysis delving into the systematics, biogeography, and conservation of this remarkable genus from open vegetation formations in Brazil.

Flowers of Leguminosae, the third largest angiosperm family, display outstanding diversity and are adapted to different modes of pollination. However, floral nectar is their most common and important reward. The morphology and position of the specialized floral nectaries (FNs) have been described only in the minority of legumes to date, so the investigation of these structures requires a further progress. The exact origin of these nectaries in legumes has been a matter of debate for more than a century. It was hypothesized that FNs are either of staminal origin or have no homology with any floral organs. This paper is devoted to the morphological study, using scanning electron microscopy (SEM), of the floral nectaries in seven taxa of the tribe Phaseoleae, with a focus on their localization, timing of their emergence, symmetry, along with a discussion of their possible identity. Some features of the androecium morphology potentially related to the interaction with pollinators were also studied. Although FNs have an annular habit in all studied species, they possess some features of monosymmetry, such as bilabiate shape or uneven distribution of secretory stomata. These FNs emerge late in ontogeny when all other floral parts are already differentiated and may be either free from other floral parts or adnate to the hypanthium. It is hypothesized that the leguminous FNs are not derived from stamens but represent structures sui generis although their spatial patterning is most probably dependent on some pentamerous floral whorl(s), i.e., a perianth or an androecium.

Ecological anatomy studies seek to link structural aspects to environmental pressures, improving knowledge about the occurrence and distribution of species. Orchidaceae is a group with high species richness and ecological diversity, well represented in the Brazilian Atlantic Forest, a biodiversity hotspot. The Iguaçu National Park (ParNa Iguaçu) is an important remnant of the southern Brazilian Atlantic Forest with a high richness of Orchidaceae. Given the family's diversity and the relevance of ecological anatomy studies for interpreting traits associated with the survival of plants in certain environments, we studied 38 species of Orchidaceae from ParNa Iguaçu, seeking to identify possible functional groups. For this, we surveyed 57 leaf morpho-anatomical characters and conducted histochemical and statistical tests. The morpho-anatomical traits group the species into two functional groups, with Cyclopogon congestus emerging isolated. In group A, xeromorphic morphoanatomical characters predominate, and group B combines members with meso/hygromorphic characteristics. We advocate the importance of understanding the ecological behavior of species, especially Orchidaceae, due to their important ecological role, in conservation actions in protected areas. Furthermore, our results highlight the morphological and anatomical diversity of the Orchidaceae found in ParNa Iguaçu, as well contributing to the development of better management practices for these plants, considering the threats posed by the opening of clearings and climate change.

Human activities and climate crises have resulted in severe disturbances affecting tropical forests. Here, we address the responses of leafless Vanilla spp. to open habitats, drought, and scarcity of large trees as phorophytes, with a focus on the root system. First, we compared the abundance of vanilla plants and root morphology in conserved and degraded forests. Next, we analysed the variations in root anatomical traits along a rainfall gradient. Our results showed contrasting responses depending on the ecoregion. In the northern humid forest, both the density of phorophytes and the number of vanillas per phorophyte were higher in the degraded forest than in the conserved forest. No such effects were observed in the southern dry forest. Furthermore, vanilla vines in the degraded humid forest developed more filiform roots for anchorage to smaller supports. Vanilla species occurring in semiarid climates, such as V. bosseri and V. decaryana, have larger underground roots with a thicker cortex to compensate for water rarity, as well as more vascular bundles to promote hydraulic conductivity, and more aerenchyma to decrease radial transport. Xylem vessel diameter is a plastic trait that increases with drought severity, as observed in one V. madagascariensis ecotype. These findings underline the high plasticity of the root system in leafless Vanilla spp. when facing habitat degradation and drought, and provide insights into their possible use in conservation and crop breeding.

Dendrobium Sw. is one of the three largest genera in Orchidaceae, which has been disputed due to controversial taxonomy and difficult species identification. Leaf morpho-anatomy of five sect. Stachyobium species from China were investigated using microscope and paraffin section to provide anatomic evidence for taxonomic significance. (1) Leaf size and apex of blade were varied among species and could be used for species delimitation. (2) Two shapes of ordinary epidermal cell were recognized, consisting of narrow-polygonal cell and broad-polygonal cell. The adaxial ordinary epidermal cells were conspicuously larger than the abaxial epidermal cell. The anticlinal wall of ordinary epidermal cells was straight-arched, with obvious thickenings. Peltate glandular trichomes occurred on both sides of leaf blade, with higher density on the abaxial surface. (3) Tetracytic stomata was observed only in D. compactum, while co-occurrence of tetracytic and anomocytic stomata was found in other four species. (4) Two types of outlines of leaf midrib were recognized, including flat type and carinate type. (5) The bicollateral vascular bundle was only observed in D. strongylanthum, but the amphivasal vascular bundle was commonly observed in the rest four species. (6) Two types of peltate trichome were firstly described anatomically, including a uni-celled stalk type and a bi-celled stalk type. Two types of crystals were present in idioblasts, including the spherical silica body in D. sinominutiflorum, and prismatic crystal in the rest four species. The monophyletic sect. Stachyobium was strongly supported by a comparative morpho-anatomy of leaf. Some morpho-anatomic features were selected and used for species discrimination and taxonomy of Dendrobium, including leaf size, leaf shape, apex of blade, the ordinary epidermal cell shape, stomatal density, leaf midrib outline, type of vascular bundle, anatomic type of peltate trichome, and crystals. Additionally, a key to five sect. Stachyobium species from China was proposed based on leaf morpho-anatomical features.

Even today, the evolutionary origin of coniferous pollen-cones is still controversial and conflicting theories about the identity of their microsporangiophores exist. Previous studies strongly suggest that the simple pollen-cone structure of some Taxaceae s.l. is most likely derived from a compound structure and each microsporangiophore represents a lateral, however markedly reduced flower. To test if a similar evolutionary pathway remembering the pseudathium concept sensu Wettstein applies also for Pinaceae, normal shaped and abnormal pollen-cones of Pinus bungeana (Pinaceae) are investigated with SEM and paraffin microtome technique. Pinus sylvestris, which is the type species of the genus, is used as another example. The early development of bisporangiate microsporangiophores starts with two distinct primordia. They fuse in basal parts and form a common stalk. The distal parts remain free and each develops a stalk, a distinct phyllom-like scutellum and one abaxial microsporangium. In some bisporangiate microsporangiophores two monosporangiate microsporangiophores are inserted laterally at the common stalk, which forms a distinct terminal apex. Other microsporangiophores bear a subunit in form of a second, however, aborted microsporangiophore in a lateral position at the base of the common stalk. It is suggested that the bisporangiate microsporangiophore is not a staminate leaf in the sense of a microsporophyll, but a dorsiventral synangium consisting at least of two fused microsporangiophores. In this case each microsporangiophore corresponds to a markedly reduced cone (= flower) which however has lost its pherophyll (= subtending leaf). Similar as shown for Torreya the simple pollen-cone structure in Pinaceae is thus derived from a pseudanthial (= compound) origin.

The white birch (Betula platyphylla Suk.) is widespread in eastern Asia, and its bark is a valuable resource for secondary metabolite extraction. Limited information is available regarding seasonal variations of secondary metabolites in white birch bark. In our study, we analyzed the phenolic compound contents and bioactivities of white birch bark in different seasons and their relationship to climatic factors and soil properties. The data suggested that the levels of total phenol, total flavonoid, seven individual phenolic compounds, and bioactivities all peaked in September. The antioxidant activity was positively correlated with the contents of phenolic compounds. Soil microbial properties like microbial biomass nitrogen (MBN) and soil urease activities (URE) explained more than 40 % of the variation in phenolic compound contents. This study highlighted that seasons regulate the contents of phenolic compounds and bioactivities by influencing soil microbial properties. The soil with low microbial activity was more favorable for the accumulation of secondary metabolites.

Conservation of parasites is not as appealing as in the case of free-living organisms. Although this is worst for animal parasites, parasitic plants — and mistletoes in particular — are considered a menace to trees and shrubs, and as so, there is a prevailing sentiment that they should be eradicated rather than protected. To deconstruct this perception, we answered three important questions: Why, what, and how to protect mistletoes? Then, based on those questions, we propose a conservation plan, especially designed for tropical species. For the Why question, we briefly reviewed the functional roles of mistletoes worldwide and provided evidence of their positive impact on other species and ecosystem functioning. For the What question, we used a framework to identify the main threats to mistletoes and commented on each one of them using world examples. Then, we used the Geocat tool to map and calculate the Extent of Occurrence (EOO) and Area of Occupancy (AOO) for each endemic and rare Brazilian mistletoe species, as an example to aid in tropical mistletoe conservation. Finally, for the How question, we listed practical recommendations to create a plan for conserving endemic and rare tropical mistletoes.

Staggered flowering phenology in sympatric plant species that share pollinators is often considered the ultimate strategy for avoiding pollinator competition or a facilitative strategy to maintain pollinators throughout the year. Some factors of the abiotic environment may also contribute to the maintenance of staggered flowering. Flowering (a)synchrony among conspecifics is recognized as a trait with selective value. However, little research has addressed phenotypic selection for (a)synchrony with other plant species. Here, I experimentaly examined the flowering phenology of two sympatric congeneric species (Cnidoscolus aconitifolius & C. souzae) that share pollinators and measured phenotypic selection on this trait. Preliminary field observation suggests that these species exhibit staggered flowering, so my main goal was to assess phenotypic selection on flowering (a)synchrony between the two study species (interspecific synchrony). I predicted that the plants that present greater interspecific synchrony would be selected against and would thus contribute to the maintenance of staggered flowering. However, the patterns of phenotypic selection found were counterintuitive: individuals of C. souzae with greater intraspecific synchrony were selected against, while those with greater interspecific synchrony with C. aconitifolius were favoured by phenotypic selection. I also found the opposite pattern of flower production response to temperature in this system, implying that the abiotic environment could partly explain the occurrence of staggered flowering. Since the phenotypic selection found in this study may select against the observed staggered flowering, reciprocal phenotypic selection between co-occurring plants cannot be invoked as a mechanism underlying staggered flowering phenology in these two Cnidoscolus species.

The subtribe Pleurothallidinae encompasses approximately 48 genera, with Pabstiella standing out due to its 133 species, many of which are found in Brazil's Atlantic Forest. Molecular data strongly support the genus and its ten sections. However, only a few species have been anatomically described, and a comprehensive characterization of the genus for comparative purposes is still needed. Our study aimed to examine the main vegetative morphoanatomical characters of the root, stem, and leaves, and analyze their evolution based on the phylogeny of the genus. We analysed root, stem, and leaf samples from 57 species using light and scanning electron microscopy. We selected 35 characters and mapped them onto the molecular phylogeny. Pabstiella exhibits homogeneous leaf anatomy, with aquiferous tissue on both sides and chlorophyllous parenchyma in the middle, aligned with vascular bundles. The ramicaul anatomy displays a simple epidermis with primary or secondary walls, a simple to stratified hypodermis, a parenchymatous or aerenchymatous cortex, and a sheath of sclerenchyma surrounding the vascular bundles. The roots endovelamen cells are larger than those in the epivelamen, reticulated tilosomes of varying morphotypes, and giant cells in the cortex. Despite the common occurrence of homoplasy among vegetative traits, particularly in the leaves, our analyses revealed several synapomorphies for the genus. These include the presence of giant cells in the root cortex, endovelamen cells larger than those of the epivelamen, a specific distribution pattern of tilosomes, and 2–3 layers of aquifer tissue on the adaxial face of the leaf. Additionally, for the Pabstiella section, a lignified stem epidermis wall is a synapomorphic character state. Our findings demonstrate that vegetative morpho-anatomy is a useful diagnostic character for generic and infrageneric categories within the genus. When analysed from a phylogenetic perspective, it contributes to our comparative understanding of the genus.