The use of DNA sequence data in plant systematics has brought us closer than ever to formulating well-founded hypotheses about phylogenetic relationships, and phylogenetic research keeps on revealing that plant genera as traditionally circumscribed often are not monophyletic. Here, we assess the monophyly of all genera of vascular plants found in Germany. Using a survey of the phylogenetic literature, we discuss which classifications would be consistent with the phylogenetic relationships found and could be followed, provided monophyly is accepted as the primary criterion for circumscribing taxa. We indicate whether and which names are available when changes in generic assignment are made (but do not present a comprehensive review of the nomenclatural aspects of such names). Among the 840 genera examined, we identified c. 140 where data quality is sufficiently high to conclude that they are not monophyletic, and an additional c. 20 where monophyly is questionable but where data quality is not ye...
4 December 2021 in Plant Systematics and Evolution
The tribe Cunonieae comprises five genera and 214 species of shrubs and trees currently distributed in the Southern Hemisphere and the tropics, exhibiting an amphi‐Pacific disjunct distribution shared with Araucariaceae, Myrtaceae, Nothofagaceae, Podocarpaceae, and Proteaceae, among others. To address the central question of how historical geological forces have shaped the distribution of plant diversity in the southern hemisphere, we aimed to provide evidence from the biogeographical history of Cunonieae. We generated the most densely sampled phylogenetic trees of Cunonieae available to date, with 121 samples and 81 species, based on 404 new sequences of plastid and nuclear DNA regions with high hierarchical phylogenetic signal ( matK , trnL‐F , rpl16 , and internal transcribed spacer (ITS)). We included 184 samples of Rosids to estimate divergence times using fossil calibration points. For biogeographic inference, we employed a time‐stratified model including fossils as tips. Cunonia and Pterophylla were paraphyletic in the ITS tree, and Cunonia was paraphyletic in the plastid tree. Pancheria , Vesselowskya , and Weinmannia were monophyletic, the latter with conflicting nuclear and plastid phylogenies. The crown group Cunonieae was dated at ~56 Ma, and its ancestral areas were Antarctica and Patagonia. Antarctica acted as a bridge between Australia and South America before the consolidation of the Antarctic Ice Sheet and the extinction of the lineage in Antarctica from the Oligocene to the Miocene. Following that, Cunonieae spread to lower latitudes via Zealandia/Oceania and Patagonia/South America. Geological changes during the Pliocene facilitated a further burst in diversification along the Andes, in Madagascar, and in New Caledonia, where at least three colonization events occurred.
The distinction of the annual Sagina apetala and S. micropetala (= S. apetala subsp. erecta, S. filicaulis) is based mainly on the position of sepals in fruit and shape and colour of the sepals, but identification of the two species is difficult. A molecular phylogeny of material identified as S. apetala and S. micropetala as well as other species of the genus using two nuclear and two plastid markers showed that there exist two lineages that are sister to each other and can be unambiguously distinguished molecularly. Although many of the morphological characters used in the literature proved useful in distinguishing these two lineages, sepal indumentum is the most reliable character to discriminate between them in Germany. Whereas S. micropetala usually has glabrous sepals, the sepals of S. apetala usually are glandular-pubescent. The chromosome number of 2n = 12 for S. micropetala, here determined for the first time, is identical to that of S. apetala, supporting the close relationship between the two species. Sagina apetala and S. micropetala are sister to S. maritima, an annual species from European coasts, which may imply a coastal origin of the two species. A brief review of the possible origin of other European ruderals from coastal relatives is provided. Citation: Dillenberger M. S. & Kadereit J. W. 2022: The distinction between Sagina apetala and S. micropetala (Caryophyllaceae: Sagineae), their phylogenetic relationships, and a note on the coastal origin of some widespread ruderals. – Willdenowia 52: 5–23. Version of record first published online on 10 February 2022 ahead of inclusion in April 2022 issue.
The name Spergularia nobreana, originally published by G. A. Sampaio from plants collected in Portugal, is investigated. A lectotype and two isolectotypes are designated on specimens preserved at PO. On the basis of a careful examination of these exsiccata, this taxon cannot be ascribed to the genus Sagina (as reported in POWO and IPNI databases where this name was considered as a synonym of Sa. hawaiensis) since it has stipules (absent in Sagina). The whole morphology of Sp. nobreana agrees with the current concept of Spergularia. The combination of characters [perennial plant, glabrous (finely glandular only in the inflorescence part); stipules triangular to lanceolate 2–3 mm long; flowers with five styles and ten stamens; sepals 4-6 mm long; capsule about 4 mm long, opening into five valves; seeds winged (wings entire or with gland-tipped papillae at the margin, brownish, less than 1/2 wide than the seeds) and unwinged] match the current concept of Sp. media s. l. Therefore, a new synonymization is proposed.