Cleomaceae is a small pantropical family that is emerging as a promising system to investigate C4 photosynthesis, floral evolution, and comparative genomics. However, our understanding of these phenomena is hindered by a lack of a strong phylogenetic hypothesis, despite a number of previous studies. We reconstructed the phylogeny of the family using data from all three genomes, including three cpDNA (ndhF, matK, ycf1), one mtDNA (rps3), and one nrDNA (ITS) regions. Analyses strongly supported 15 clades: (1) Clade 1, which includes two Old World species, Cleome khorassanica and C. turkmena; (2) Cleome s.str., which includes the type C. ornithopodioides and Old World species; (3) Droserifolia, corresponding to three Old World species, C. droserifolia, C. fimbriata, C. quinquenervia; (4) Polanisia, equivalent to this New World genus; (5) Angustifolia, which includes four Old World species; (6) North American cleomoids, which includes four genera, Cleomella, Peritoma, Oxystylis, and Wislizenia; (7) Australian, which includes Old world species and worldwide weed Arivela viscosa; (8) Gynandropsis, equivalent to this monotypic genus; (9) Clade 6, which includes Old World species of Cleome and Dipterygium; (10) Dactylaena, corresponding to this genus and Physostemon; (11) African, which includes species distributed in Old World; (12) Andean, which includes Podandrogyne and tropical New World species of Cleome; (13) Melidiscus, which includes New World tropical species; (14) Cleoserrata, which includes New World tropical species; and (15) Tarenaya, a large New World clade. Major relationships amongst the clades are strongly supported for the first time, including North American cleomoids sister to all remaining Cleomaceae. While five genera are confirmed or newly identified here to be non‐monophyletic (Cleome, Cleomella, Hemiscola, Peritoma, Tarenaya), six are supported (Cleoserrata, Dactylaena, Melidiscus, Physostemon, Podandrogyne, Polanisia). Thus, there are many taxonomic and evolutionary implications to our revised phylogenetic hypothesis.

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Questions The impact of invasive species on community structure and function varies, yet it is difficult to predict. Different hypotheses have been proposed to predict invasive species establishment and impact on resident communities, based on characteristics of the resident community and/or environmental conditions. Invasive species, however, interact with both native and exotic species. The interaction with exotic species is important, as it can result in secondary invasion or greater impact on native species. Smooth brome (Bromus inermis Leyss.) is a widely planted forage crop, but also a harmful invasive species in North American grasslands, yet little is known about the variability of its impact on resident communities. We ask (1) whether smooth brome has a consistent impact on community structure and function; (2) which biotic and abiotic conditions are associated with smooth brome's impact on resident communities; and (3) whether smooth brome has a similar impact on native and exotic species, and which biotic or abiotic conditions drive the interaction of smooth brome with native and exotic species. Location Eight grasslands throughout Alberta, Canada. Methods We used space‐for‐time substitutions to quantify smooth brome's impact on different aspects of community structure and function, and whether it varies depending on species richness, productivity, temperature, precipitation and variation in precipitation. Results Smooth brome had a consistent negative impact on community structure and function. However, the strength of the effect depended on aspects of the local community. Smooth brome impacts on species richness were higher in species‐rich areas, while impact on resident species biomass was larger in productive, warmer and more variable sites. In most sites the negative effect of smooth brome on species richness was higher for native species, compared to exotics. Impact on native and exotic species richness was larger in species‐rich and more variable sites, respectively. Conclusions Understanding and predicting smooth brome's impact on community structure and function can help managers prescribe management plans to reduce negative impacts of smooth brome on native communities. Predicting the interaction of smooth brome with exotic species may be just as important when planning management strategies, to avoid secondary invasion and/or the accumulation of exotic species.

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