Angiosperms are the cornerstone of most terrestrial ecosystems and human livelihoods^1,2. A robust understanding of angiosperm evolution is required to explain their rise to ecological dominance. So far, the angiosperm tree of life has been determined primarily by means of analyses of the plastid genome^3,4. Many studies have drawn on this foundational work, such as classification and first insights into angiosperm diversification since their Mesozoic origins^5–7. However, the limited and biased sampling of both taxa and genomes undermines confidence in the tree and its implications. Here, we build the tree of life for almost 8,000 (about 60%) angiosperm genera using a standardized set of 353 nuclear genes⁸. This 15-fold increase in genus-level sampling relative to comparable nuclear studies⁹ provides a critical test of earlier results and brings notable change to key groups, especially in rosids, while substantiating many previously predicted relationships. Scaling this tree to time using 200 fossils, we discovered that early angiosperm evolution was characterized by high gene tree conflict and explosive diversification, giving rise to more than 80% of extant angiosperm orders. Steady diversification ensued through the remaining Mesozoic Era until rates resurged in the Cenozoic Era, concurrent with decreasing global temperatures and tightly linked with gene tree conflict. Taken together, our extensive sampling combined with advanced phylogenomic methods shows the deep history and full complexity in the evolution of a megadiverse clade.

Genome size is a biodiversity trait that shows staggering diversity across eukaryotes, varying over 64,000-fold. Of all major taxonomic groups, land plants stand out due to their staggering genome size diversity, ranging ca. 2400-fold. As our understanding of the implications and significance of this remarkable genome size diversity in land plants grows, it is becoming increasingly evident that this trait plays not only an important role in shaping the evolution of plant genomes, but also in influencing plant community assemblages at the ecosystem level. Recent advances and improvements in novel sequencing technologies, as well as analytical tools, make it possible to gain critical insights into the genomic and epigenetic mechanisms underpinning genome size changes. In this review we provide an overview of our current understanding of genome size diversity across the different land plant groups, its implications on the biology of the genome and what future directions need to be addressed to fill key knowledge gaps.

Summary: The genome evolution of ferns has been considered to be relatively static compared with angiosperms. In this study, we analyse genome size data and chromosome numbers in a phylogenetic framework to explore three hypotheses: the correlation of genome size and chromosome number, the origin of modern ferns from ancestors with high chromosome numbers, and the occurrence of several whole‐genome duplications during the evolution of ferns. To achieve this, we generated new genome size data, increasing the percentage of fern species with genome sizes estimated to 2.8% of extant diversity, and ensuring a comprehensive phylogenetic coverage including at least three species from each fern order. Genome size was correlated with chromosome number across all ferns despite some substantial variation in both traits. We observed a trend towards conservation of the amount of DNA per chromosome, although Osmundaceae and Psilotaceae have substantially larger chromosomes. Reconstruction of the ancestral genome traits suggested that the earliest ferns were already characterized by possessing high chromosome numbers and that the earliest divergences in ferns were correlated with substantial karyological changes. Evidence for repeated whole‐genome duplications was found across the phylogeny. Fern genomes tend to evolve slowly, albeit genome rearrangements occur in some clades.

The new outline of relationships in basal branches of the family Compositae Giseke confirms that the sister group to the tribe Cardueae Cass. are not Mutisieae Cass., but rather a group of African genera now classified as the tribe Tarchonantheae Kostel. This change implies that the monophyly of the Cardueae must be reassessed on a molecular basis. Moreover, new collections in recent years allow us to extend our sampling to 70 of the 74 genera of the tribe. We performed a new molecular study of the tribe using one nuclear region (ITS) and two chloroplastic markers (trnL-trnF and matK) in addition to a more appropriate outgroup. Our results confirm that the Cardueae is a natural group but indicate some changes in subtribal delineation: the subtribe Cardopatiinae Less. is recognized and some genera are moved to other subtribes (Myopordon Boiss., Nikitinia Iljin, Syreitschikovia Pavlov, and the Xeranthemum L. group). A recapitulation of a number of interesting questions that remain unresolved in the... Resumen El nuevo esquema de las relaciones en las ramas basales de la familia Compositae Giseke ha confirmado que el grupo hermano de la tribu Cardueae Cass. no es la tribu Mutisieae Cass., sino más bien un grupo de géneros africanos que ahora se clasifican como tribu Tarchonantheae Kostel. Este cambio implica que la monofilia de las Cardueae establecida sobre bases moleculares debe confirmarse. Además, nuestras nuevas recolecciones en los últimos años hacen que nuestro muestreo se extienda a 70 de los 74 géneros de la tribu. Hemos llevado a cabo un nuevo estudio molecular de la tribu usando una región nuclear (ITS) y dos cloroplásticas, además de seleccionar un grupo externo más adecuado. Nuestros resultados confirman que las Cardueae son un grupo natural, pero aconsejan algunos cambios en la delimitación subtribal: el reconocimiento de la subtribu Cardopatiinae Less. y el cambio de algunos géneros a otras subtribus (Myopordon Boiss., Nikitinia Iljin, Syreitschikovia Pavlov y el grupo Xeranthemum L.). Pr...