The Macaronesian laurel forests (MLF) are dominated by trees with a laurophyll habit comparable to evergreen humid forests which were scattered across Europe and the Mediterranean in the Paleogene and Neogene. Therefore, MLF are traditionally regarded as an old, 'Tertiary relict' vegetation type. Here we address the question if key taxa of the MLF are relictual. We evaluated the relict hypothesis consulting fossil data and analyses based on molecular phylogenies of 18 representative species. For molecular dating we used the program BEAST, for ancestral trait reconstructions BayesTraits and Lagrange to infer ancestral areas. Our molecular dating showed that the origins of four species date back to the Upper Miocene while 14 originated in the Plio-Pleistocene. This coincides with the decline of fossil laurophyllous elements in Europe since the middle Miocene. Ancestral trait and area reconstructions indicate that MLF evolved partly from pre-adapted taxa from the Mediterranean, Macaronesia and the tropics. According to the fossil record laurophyllous taxa existed in Macaronesia since the Plio- and Pleistocene. MLF are composed of species with a heterogeneous origin. The taxa dated to the Pleistocene are likely not 'Tertiary relicts'. Some species may be interpreted as relictual. In this case, the establishment of most species in the Plio-Pleistocene suggests that there was a massive species turnover before this time. Alternatively, MLF were largely newly assembled through global recruitment rather than surviving as relicts of a once more widespread vegetation. This process may have possibly been triggered by the intensification of the trade winds at the end of the Pliocene as indicated by proxy data.
Numerous taxa of Hebeloma have been reported in association with Salix, Dryas, and Betula in arctic-alpine habitats. However, species are notoriously difficult to delineate because morphological features overlap, and previously there was little reliable molecular data available. Recent progress in ITS-sequencing within the genus, coupled with an extensive database of parametrically described collections, now allows comparisons between species and their distributions. Here we report 16 species of Hebeloma from the Rocky Mountain alpine zone from some of the lowest latitudes (latitude 36°–45°N) and highest elevations (3000–4000 m) for arctic-alpine fungi in the northern hemisphere. Twelve of these species have been reported from arctic-alpine habitats in Europe and Greenland and are now molecularly confirmed from the Middle and Southern Rockies, greatly expanding their distribution. These are: Hebelomaalpinum, H.aurantioumbrinum, H.dunense, H.hiemale, H.marginatulum, H.mesophaeum, H.nigellum, H.oreophilum, H.subconcolor, H.spetsbergense, H.vaccinum, and H.velutipes. Hebelomahygrophilum is known from subalpine habitats in Europe, but was never recorded in arctic-alpine ecology. Three species recorded from the Rockies, but as yet not reported from Europe, are H.alpinicola, H.avellaneum, and H.excedens. The last two have never previously been reported from an arctic-alpine habitat. For all three of these species, the holotypes have been studied morphologically and molecularly, and have been incorporated into the analysis.
Hebeloma velutipes is one of the most common and abundant members of the ectomycorrhizal basidiomycete genus and H. sinapizans is one of its oldest and most commonly recorded species. Using large sample sizes, several loci and the analysis of types, we explored the taxonomy, species limits, distribution and the infrageneric classification of these two species and their relatives. By relying almost exclusively on sequenced material, we were able to attain a marked refinement of species descriptions. Phylogenetic results are congruent with respect to the delimitation of species, but suggest conflicting evolutionary histories of the species phylogeny. Using multi-species coalescent analysis, phylogenetic support for H. sects. Velutipes and Sinapizantia was assessed, finding clear support for H. sect. Sinapizantia but ambiguous results for H. sect. Velutipes. One species, H. subconcolor, previously accommodated in H. sect. Denudata, is placed in H. sect. Velutipes. Hebeloma bulbiferum, so far not considered in systematic treatments, is shown to belong to H. sect. Sinapizantia. Unexpectedly, H. velutipes turned out to be distinct from H. leucosarx. Hebeloma erebium comb. nov., H. celatum sp. nov. and H. quercetorum, formerly treated as a single species (H. quercetorum), are demonstrated to be three taxa that are clearly distinct in molecular terms, even though, morphologically, they can be deceptively similar; H. erebium and H. quercetorum are, moreover, geographically distinct. The morphological characters used to distinguish the ten recognised European species are outlined. Finally, a lectotype and an epitype are designated for H. sinapizans and a lectotype for H. quercetorum
According to recent taxonomic treatments, Bromeliaceae subfamily Pitcairnioideae comprise the genera Deuterocohnia, Dyckia, Encholirium, Fosterella and Pitcairnia. We present a dated molecular phylogenetic analysis of a comprehensive taxon set to enable inferences of evolution in the subfamily. Phylogenetic relationships in Pitcairnioideae were reconstructed based on three plastid loci (rpl32‐trnL, rps16‐trnK, 5′ end of matK) and the nuclear single‐copy gene PHYC exon 1, using maximum parsimony, maximum likelihood and Bayesian inference. The plastid phylogenetic analysis supports the monophyly of the subfamily, whereas the nuclear DNA data suggest a nested position of Puyoideae in Pitcairnioideae. Fosterella and Dyckia (including Encholirium) are monophyletic in both analyses, whereas Deuterocohnia is paraphyletic and Pitcairnia remains unresolved in the plastid tree. A Bayesian relaxed clock model applied to the plastid data indicates a diversification of Fosterella and Pitcairnia at c. 6–8 Mya, whereas Deuterocohnia and Dyckia might have diversified at about 2–4 Mya. Our data support the concept that Pitcairnioideae originated in the Andes, followed by numerous dispersal events to South and Central America. Plastid capture events might explain the contrasting topologies of plastid and nuclear trees in Deuterocohnia, whereas the position of Puya needs to be re‐evaluated with additional nuclear markers.
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