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Coevolutionary theory suggests that an arms race between plants and herbivores yields increased plant specialized metabolite diversity and the geographic mosaic theory of coevolution predicts that coevolutionary interactions vary across geographic scales. Consequently, plant specialized metabolite diversity is expected to be highest in coevolutionary hotspots, geographic regions, which exhibit strong reciprocal selection on the interacting species. Despite being well-established theoretical frameworks, technical limitations have precluded rigorous hypothesis testing. Here we aim at understanding how geographic separation over evolutionary time may have impacted chemical differentiation in the cosmopolitan plant genus Euphorbia. We use a combination of state-of-the-art computational mass spectral metabolomics tools together with cell-based high-throughput immunomodulatory testing. Our results show significant differences in specialized metabolite diversity across geographically separated phylogenetic clades. Chemical structural diversity of the highly toxic Euphorbia diterpenoids is significantly reduced in species native to the Americas, compared to Afro-Eurasia. The localization of these compounds to young stems and roots suggest a possible ecological relevance in herbivory defense. This is further supported by reduced immunomodulatory activity in the American subclade as well as herbivore distribution patterns. We conclude that computational mass spectrometric metabolomics coupled with relevant ecological data provide a strong tool for exploring plant specialized metabolite diversity in a chemo-evolutionary framework.

Coevolutionary theory suggests that an arms race between plants and herbivores yields increased plant specialized metabolite diversity and the geographic mosaic theory of coevolution predicts that coevolutionary interactions vary across geographic scales. Consequently, plant specialized metabolite diversity is expected to be highest in coevolutionary hotspots, geographic regions, which exhibit strong reciprocal selection on the interacting species. Despite being well established theoretical frameworks, technical limitations have precluded rigorous hypothesis testing. Here we aim at understanding how geographic separation over evolutionary time may have impacted chemical differentiation in the cosmopolitan plant genus Euphorbia. We use a combination of state-of-the-art computational mass spectral metabolomics tools together with cell-based high-throughput immunomodulatory testing. Our results show significant differences in specialized metabolite diversity across geographically separated phylogenetic clades. Chemical structural diversity of the highly toxic Euphorbia diterpenoids is significantly reduced in species native to the Americas, compared to Afro-Eurasia. The localization of these compounds to young stems and roots, suggest a possible ecological relevance in herbivory defense. This is further supported by reduced immunomodulatory activity in the American subclade as well as herbivore distribution patterns. We conclude that computational mass spectrometric metabolomics coupled with relevant ecological data provide a strong tool for exploring plant specialized metabolite diversity in a chemo-evolutionary framework.

Coevolutionary theory suggests that an arms race between plants and herbivores yields increased plant specialized metabolite diversity and the geographic mosaic theory of coevolution predicts that coevolutionary interactions vary across geographic scales. Consequently, plant specialized metabolite diversity is expected to be highest in coevolutionary hotspots, geographic regions, which exhibit strong reciprocal selection on the interacting species. Despite being well-established theoretical frameworks, technical limitations have precluded rigorous hypothesis testing. Here we aim at understanding how geographic separation over evolutionary time may have impacted chemical differentiation in the cosmopolitan plant genus Euphorbia. We use a combination of state-of-the-art computational mass spectral metabolomics tools together with cell-based high-throughput immunomodulatory testing. Our results show significant differences in specialized metabolite diversity across geographically separated phylogenetic clades. Chemical structural diversity of the highly toxic Euphorbia diterpenoids is significantly reduced in species native to the Americas, compared to Afro-Eurasia. The localization of these compounds to young stems and roots suggest a possible ecological relevance in herbivory defense. This is further supported by reduced immunomodulatory activity in the American subclade as well as herbivore distribution patterns. We conclude that computational mass spectrometric metabolomics coupled with relevant ecological data provide a strong tool for exploring plant specialized metabolite diversity in a chemo-evolutionary framework.

This work presents novelties in the genus Persicaria in Brazil. More specifically, we describe P. sylvestris, a new species from the Atlantic rainforest in subtropical Brazil, propose the new combination P. diospyrifolium and designate a lectotype for its basionym, Polygonum diospyrifolium. The new species has until now been identified as P. acuminata, from which it differs by morphological characters as well as ecological aspects. We also provide photographs of the new species and of similar species along with a distribution map and a key to the species of Persicaria in Brazil.

Here, we present evidence that the alleged correction of the typification of Tradescantia crassula recently proposed by Pellegrini, Forzza and Sakuragui is erroneous. Furthermore, we clarify misconceptions concerning the epitype of T. crassula, the specimen B-100521014, which was collected by Friedrich Sello in southern Brazil, and is not original material for T. crassula.

The flora of Santa Catarina is the best known in Brazil, and yet considerable knowledge gaps remain. Aiming at filling these gaps, we present here 55 new records of vascular plants for this Brazilian state, and the re-collection of four species after more than 50 years. About 50% of new records are non-native in the area. We present short descriptions of each of these species, citations to published illustrations, and also comments and field pictures of most of them.

This contribution presents updates to the knowledge of the species of Euphorbia that occur in Santa Catarina state, southern Brazil. More specifically, we here typify the names E. cyathophora, E. hirtella, E. paranensis and E. stenophylla, and present the first records of E. cyathophora, E. graminea, E. ophthalmica and E. thymifolia for Santa Catarina. Finally, we provide an updated identification key to all 30 species of Euphorbia that occur in Santa Catarina, including native, naturalised and cultivated species.

Here, we present evidence that the alleged correction of the typification of Tradescantia crassula recently proposed by Pellegrini, Forzza and Sakuragui is erroneous. Furthermore, we clarify misconceptions concerning the epitype of T. crassula, the specimen B-100521014, which was collected by Friedrich Sello in southern Brazil, and is not original material for T. crassula.

Melilotus albus Medik. is a cosmopolite and invasive species, native to the Old World, which in Brazil had its occurrence hitherto recorded only in the states of São Paulo, Paraná and Rio Grande do Sul. This study extends its distribution to Santa Catarina state, southern Brazil, due to the recent discovery of populations in the municipalities of Florianópolis and Xanxerê. These new records are ca. 250 km distant from the nearest records, in Paraná state, also in southern Brazil.