Angiosperms display an enormous diversity of forms, functions and strategies when it comes to reproduction. This multiplicity has been translated into several terminological concepts and contexts, which have facilitated further research. On the other hand, the use of terms that address the reproduction of flowering plants has been shown to be inconsistent in the literature, complicating communication among specialists. Key terms, such as "reproductive system", "mating system" and "sexual system", among others, have been frequently cited as synonyms, and even used in different circumstances. This review proposes to establish a consistent nomenclatural classification in the field of angiosperms reproductive biology in order to facilitate communication among researchers. Specific terms related to angiosperm reproduction are conceptualized and distributed into five general systems: four related to sexual reproduction (sexual, floral, incompatibility and mating systems); and one related to asexual reproduction (apomictic systems). Our proposal is not to establish a natural classification, but rather to provide a general overview of the main concepts that were grouped here in an artificial and functional manner. Our aim is to advance the field of reproductive biology of angiosperms with consistent and well-defined applications of relevant terminologies.

The relationship between plants and frugivorous animals is modulated by morphological and nutritional characteristics of fruits, as well as their seasonal availability across habitats. We evaluated fruiting phenology, fruit morphology and nutritional characteristics of 35 abundant plant species from 15 families associated with frugivorous birds from distinct habitats in the Cerrado (savanna, forest, and palm swamp). For a subset of 16 plant species, we also evaluated the overlap in interactions with frugivorous birds using data from the literature. Open-habitat plants had their fruiting peak during the rainy season, while fruiting of forest species was evenly distributed across the year. Plants of the same family exhibited similar fruit morphology and nutritional characteristics. Most plants had fruits with more sugars than lipids, while all species with higher lipid content were from savanna habitats and produced fruits during the rainy season, the peak reproductive season for birds. Assemblages of frugivorous birds exhibited considerable overlap, irrespective of habitat or fruiting season of plants. The complementarity found among habitats, considering seasonal availability and nutritional profile of fruits for frugivorous birds, is relevant for community maintenance and regeneration. Therefore, this landscape level complexity should always be considered in conservation and restoration policies for the Cerrado.

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Background and Aims Trap flowers are fascinating cases of adaptation, often linked to oviposition site mimicry systems. Some trap flowers do not imprison pollinators for a pre-determined period, but rather force them to move through a specific path, manipulating their movements in a way that culminates in pollen transfer, often as they leave through a secondary opening. Methods We investigated the previously unknown pollination system of the lady’s slipper orchid Phragmipedium vittatum and assessed the function of micro-morphological traits of its trap flowers. Key Results Our observations revealed that P. vittatum is pollinated by females of two hoverfly species (Syrphidae). Eggs laid by flies on or near raised black spots on the flowers indicate that the orchid mimics aphids which serve as food for their aphidophagous larvae. Dark elevated aphid-like spots appear to attract the attention of hoverflies to a slipping zone. This region has downward projecting papillate cells and mucilage secretion that promote slipperiness, causing potential pollinators to fall into the labellum. They then follow a specific upward route towards inner aphid-like spots by holding onto upward oriented hairs that aid their grip. As hoverflies are funneled by the lateral constriction of the labellum, they pass the stigma, depositing pollen they may be carrying. Later, they squeeze under one of the articulated anthers which places pollen smears onto their upper thorax. Then, they depart through one of the narrow lateral holes by holding onto hairs projecting from the petals. Conclusions This study confirms the system of aphid mimicry in Phragmipedium and highlights the sophisticated micro-morphological traits used by trap flowers in pollinator attraction, trapping, guidance, and release, thus promoting precise pollen transfer.

Several studies have suggested reasons why galls have conspicuous colours, but none of the ideas have been confirmed. However, what if the vibrant colours of some galls are explained simply by the effect of light exposure? This may lead to anthocyanin accumulation, functioning as a defence mechanism against the effects of high light. We studied the globoid galls induced by Cecidomyiidae (Diptera) on Qualea parviflora (Vochysiaceae), relating anthocyanin accumulation and chlorophyll fluorescence parameters to light incidence in abaxial and adaxial galls. We also tested if the anthocyanin accumulation patterns apply to another Cecidomyiidae‐induced gall morphotype (intralaminar) within the same plant. Adaxial galls are exposed to higher incident light, with more anthocyanin accumulation and therefore red coloration. In galls from angled leaves, the greater the angle of the leaf, the higher the difference between anthocyanins on the sun and shade sides of galls. Photosynthetic pigment concentrations did not differ between abaxial and adaxial galls. However, we found higher (Fm′ − F′)/Fm′ and Fv/Fm in the abaxial galls. Conversely, NPQ and Rfd were higher in adaxial galls. Finally, the pattern of anthocyanin accumulation was not found in the intralaminar gall. Anthocyanin accumulation in galls functions as a photoprotective strategy, maintaining tissue vitality in regions exposed to high light conditions. However, this mechanism may vary even among galls within the same host, indicating idiosyncrasy when it comes to coloration in galls. To date, this is the first study to demonstrate quantitatively why the galls of a specific species may be coloured: the variation in light regimes creates differential anthocyanin accumulation, influencing coloration.

Distyly is a floral polymorphism that promotes cross-pollination through precise pollination. Psychotria is a mostly tropical genus of distylous Rubiaceae. Although widely studied in Brazil, some regions/species are still poorly explored, which hinders the understanding of distyly system along a greater geographical range. Here, we studied a subtropical population of Psychotria brachyceras in southern Brazil. For this, we characterized morphs occurrence, reciprocity of sexual structures, mating and incompatibility systems. In addition, we compared the reciprocity values from other species of the genus based on values gathered from literature to understand how the population behaves. The population showed equal proportions of thrum (short stigma/high anthers) and pin (high stigma/short anthers) morphs. Reciprocity was higher than the average for the genus and inaccuracy values between sexual organs were evenly distributed between the organ types, indicating a trend to typical distyly. Higher fruit set rates in intermorph and open pollination treatments and pollen tube growth observations confirmed that the population has a functional heteromorphic incompatibility system. Psychotria brachyceras showed no signs of distinct traits to typical distylous populations, which seems to ensure reproductive success and distyly maintenance.

Rewardless orchid species are pollinated by deception and have reduced reproductive success. Those species that present self‐compatibility followed by alternative mechanisms of autogamy may compensate for such episodic allogamy events. This is the case for rain‐assisted self‐pollination, a rare mechanism in Orchidaceae. In this study, we investigated the reproductive biology of two terrestrial species: Cyrtopodium hatschbachii and C. paludicolum. We studied their reproductive systems, examined pollinators and male and female successes, and ascertained if rain promotes self‐pollination. Both species are allogamous but self‐compatible. However, natural fruit set is low, not exceeding 1.40% during 4 years of observation. This may result from the reduced frequency of pollinator visitation followed by a high pollinator specificity, because each species was pollinated by a single specialist bee. Although spontaneous selfing did not occur, we verified fruits formed by rain action. The evaporation of the water droplet that accumulates on stigma helps the pollinarium to slip back, promoting selfing. This occurred in approximately 10% of C. hatschbachii fruits, but in C. paludicolum it was recorded only once during three observation years. This indicates that the phenomenon happens at random and may vary temporally. Nevertheless, rain may confer additional fruit set, especially under circumstances of pollinator limitation. Overall, we confirmed deception as a strategy for this understudied genus. In addition, we report a further two cases of rain‐assisted self‐pollination for Cyrtopodium, for species from the center of diversity of the genus, indicating that it may be more widespread than previously thought.

The coexistence of phylogenetically related species is an attractive topic because of the potentially intense interspecific competition. The most often investigated mechanisms mediating coexistence of these species are environmental filtering and niche partitioning. However, the role of other factors, such as species-specific parasites, is still poorly understood. Along the riparian understory of a tropical forest, we explored niche occupation and coexistence between Chrysso intervales and Helvibis longicauda, two related syntopic web-building spiders. We also investigated the effect of H. longicauda mortality induced by a specific fungus parasite, Gibellula pulchra, on the dynamic of C. intervales spatial distribution. Coexistence was mediated mainly by a fine-scale horizontal spatial segregation. H. longicauda built webs almost exclusively close to the river, while C. intervales occupied adjacent areas (10-20 m away from margins). We also found differentiation in other niche dimensions that might allow coexistence, such as in plants occupied, height of web placement, width of leaves used for thread attachment and phenology. H. longicauda mortality caused by fungi was higher during winter than in summer. Consequently, the abundance of C. intervales increased at distances close to the river, indicating competitive release through a density-mediated indirect effect. This demonstrates how non-competitive specific-antagonists can indirectly affect other non-hosts competing community members and influence their spatial distribution in fine-scale ranges. We suggest that environmental filtering restricts H. longicauda to cooler regions; niche partitioning leads populations to occupy different vertical strata and competitive exclusion precludes C. intervales to reach river margins, generating an unusual horizontal zonation pattern.