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Model species continue to underpin groundbreaking plant science research. At the same time, the phylogenetic resolution of the land plant Tree of Life continues to improve. The intersection of these two research paths creates a unique opportunity to further extend the usefulness of model species across larger taxonomic groups. Here we promote the utility of the Arabidopsis thaliana model species, especially the ability to connect its genetic and functional resources, to species across the entire Brassicales order. We focus on the utility of using genomics and phylogenomics to bridge the evolution and diversification of several traits across the Brassicales to the resources in Arabidopsis, thereby extending scope from a model species by establishing a “model clade”. These Brassicales-wide traits are discussed in the context of both the model species Arabidopsis thaliana and the family Brassicaceae. We promote the utility of such a “model clade” and make suggestions for building global networks to support future studies in the model order Brassicales.

Differentiating sieve elements in the phloem of angiosperms produce abundant phloem-specific proteins before their protein synthesis machinery is degraded. These P-proteins initially form dense bodies, which disperse into individual filaments when the sieve element matures. In some cases, however, the dense protein agglomerations remain intact and are visible in functional sieve tubes as non-dispersive P-protein bodies, or NPBs. Species exhibiting NPBs are distributed across the entire angiosperm clade. We found that NPBs in the model tree,Populus trichocarpa, resemble the protein bodies described from other species of the order Malpighiales as they all consist of coaligned tubular fibrils bundled in hexagonal symmetry. NPBs of all Malpighiales tested proved unresponsive to sieve tube wounding and Ca²⁺. TheP. trichocarpaNPBs consisted of a protein encoded by a gene that in the genome database of this species had been annotated as a homolog ofSEOR1(sieve element occlusion-related 1) inArabidopsis. Sequencing of the gene in our plants corroborated this interpretation, and we named the genePtSEOR1. Previously characterized SEOR proteins form irregular masses of P-protein slime in functional sieve tubes. We conclude that a subgroup of these proteins is involved in the formation of NPBs at least in the Malpighiales, and that these protein bodies have no role in rapid wound responses of the sieve tube network.

Phylogenetic studies ofCarexL. (Cyperaceae) have consistently demonstrated that most subgenera and sections are para‐ or polyphyletic. Yet, taxonomists continue to use subgenera and sections inCarexclassification. Why? The GlobalCarexGroup (GCG) here takes the position that the historical and continued use of subgenera and sections serves to (i) organize our understanding of lineages inCarex, (ii) create an identification mechanism to break the ~2000 species ofCarexinto manageable groups and stimulate its study, and (iii) provide a framework to recognize morphologically diagnosable lineages withinCarex. Unfortunately, the current understanding of phylogenetic relationships inCarexis not yet sufficient for a global reclassification of the genus within a Linnean infrageneric (sectional) framework. Rather than leavingCarexclassification in its current state, which is misleading and confusing, we here take the intermediate steps of implementing the recently revised subgeneric classification and using a combination of informally named clades and formally named sections to reflect the current state of our knowledge. This hybrid classification framework is presented in an order corresponding to a linear arrangement of the clades on a ladderized phylogeny, largely based on the recent phylogenies published by the GCG. It organizesCarexinto six subgenera, which are, in turn, subdivided into 62 formally named Linnean sections plus 49 informal groups. This framework will serve as a roadmap for research onCarexphylogeny, enabling further development of a complete reclassification by presenting relevant morphological and geographical information on clades where possible and standardizing the use of formal sectional names.

The megadiverse genusCarex(c. 2000 species, Cyperaceae) has a nearly cosmopolitan distribution, displaying an inverted latitudinal richness gradient with higher species diversity in cold‐temperate areas of the Northern Hemisphere. Despite great expansion in our knowledge of the phylogenetic history of the genus and many molecular studies focusing on the biogeography of particular groups during the last few decades, a global analysis ofCarexbiogeography and diversification is still lacking. For this purpose, we built the hitherto most comprehensiveCarex‐dated phylogeny based on three markers (ETS–ITS–matK), using a previous phylogenomic Hyb‐Seq framework, and a sampling of two‐thirds of its species and all recognized sections. Ancestral area reconstruction, biogeographic stochastic mapping, and diversification rate analyses were conducted to elucidate macroevolutionary biogeographic and diversification patterns. Our results reveal thatCarexoriginated in the late Eocene in E Asia, where it probably remained until the synchronous diversification of its main subgeneric lineages during the late Oligocene. E Asia is supported as the cradle ofCarexdiversification, as well as a “museum” of extant species diversity. Subsequent “out‐of‐Asia” colonization patterns feature multiple asymmetric dispersals clustered toward present times among the Northern Hemisphere regions, with major regions acting both as source and sink (especially Asia and North America), as well as several independent colonization events of the Southern Hemisphere. We detected 13 notable diversification rate shifts during the last 10 My, including remarkable radiations in North America and New Zealand, which occurred concurrently with the late Neogene global cooling, which suggests that diversification involved the colonization of new areas and expansion into novel areas of niche space.