Accelerated Rates of Floral Evolution at the Upper Size Limit for Flowers

SummaryEvolutionary theory explains phenotypic change as the result of natural selection, with constraint limiting the direction, magnitude, and rate of response [1]. Constraint is particularly likely to govern evolutionary change when a trait is at perceived upper or lower limits. Macroevolutionary rates of floral-size change are unknown for any angiosperm family, but it is predicted that rates should be diminished near the upper size limit of flowers, as has been shown for mammal body mass [2]. Our molecular results show that rates of floral-size evolution have been extremely rapid in the endoholoparasite Rafflesia, which contains the world's largest flowers [3]. These data provide the first estimates of macroevolutionary rates of floral-size change and indicate that in this lineage, floral diameter increased by an average of 20 cm (and up to 90 cm)/million years. In contrast to our expectations, it appears that the magnitude and rate of floral-size increase is greater for lineages with larger flowered ancestors. This study suggests that constraints on rates of floral-size evolution may not be limiting in Rafflesia, reinforcing results of artificial- and natural-selection studies in other plants that demonstrated the potential for rapid size changes [4–6]

High diversity of root associated fungi in both alpine and arctic Dryas octopetala

<p>Abstract</p> <p>Background</p> <p><it>Dryas octopetala </it>is a widespread dwarf shrub in alpine and arctic regions that forms ectomycorrhizal (ECM) symbiotic relationships with fungi. In this study we investigated the fungal communities associated with roots of <it>D. octopetala </it>in alpine sites in Norway and in the High Arctic on Svalbard, where we aimed to reveal whether the fungal diversity and species composition varied across the Alpine and Arctic regions. The internal transcribed spacer (ITS) region of nuclear ribosomal DNA was used to identify the fungal communities from bulk root samples obtained from 24 plants.</p> <p>Results</p> <p>A total of 137 operational taxonomic units (OTUs) were detected (using 97% similarity cut off during sequence clustering) and well-known ECM genera such as <it>Cenococcum</it>, <it>Cortinarius, Hebeloma</it>, <it>Inocybe </it>and <it>Tomentella </it>occurred frequently. There was no decrease in fungal diversity with increasing latitude. The overall spatial heterogeneity was high, but a weak geographical structuring of the composition of OTUs in the root systems was observed. Calculated species accumulation curves did not level off.</p> <p>Conclusions</p> <p>This study indicates that the diversity of fungi associated with <it>D. octopetala </it>does not decrease in high latitude arctic regions, which contrasts observations made in a wide spectrum of other organism groups. A high degree of patchiness was observed across root systems, but the fungal communities were nevertheless weakly spatially structured. Non-asymptotical species accumulation curves and the occurrence of a high number of singletons indicated that only a small fraction of the fungal diversity was detected.</p

Data from: A synopsis of the saddle fungi (Helvella: Ascomycota) in Europe – species delimitation, taxonomy and typification

Helvella is a widespread, speciose genus of large apothecial ascomycetes (Pezizomycete: Pezizales) that are found in terrestrial biomes of the Northern and Southern Hemispheres. This study represents a beginning on assessing species limits and applying correct names for Helvella species based on type material and specimens in the university herbaria (fungaria) of Copenhagen (C), Harvard (FH) and Oslo (O). We use morphology and phylogenetic evidence from four loci – heat shock protein 90 (hsp), translation elongation factor alpha (tef), RNA polymerase II (rpb2) and the nuclear large subunit ribosomal DNA (LSU) –to assess species boundaries in an expanded sample of Helvella specimens from Europe. We combine the morphological and phylogenetic information from 55 Helvella species from Europe with a small sample of Helvella species from other regions of the world. Little intraspecific variation was detected within the species using these molecular markers; hsp and rpb2 markers provided useful barcodes for species delimitaion in this genus, while LSU provided more variable resolution among the pertinent species. We discuss typification issues and identify molecular characteristics for 55 European Helvella species, designate neo- and epitypes for 30 species, and describe seven Helvella species new to science, i.e., H. alpicola, H. alpina, H. carnosa, H. danica, H. nannfeldtii, H. pubescens and H. scyphoides

The Helvella corium species aggregate in Nordic countries – phylogeny and species delimitation

Mycologists have always been curious about the elaborate morphotypes and shapes of species of the genus Helvella. The small, black, cupulate Helvella specimens have mostly been assigned to Helvella corium, a broadly defined morpho-species. Recent phylogenetic analyses, however, have revealed an aggregate of species hidden under this name. We performed a multispecies coalescent analysis to re-assess species limits and evolutionary relationships of the Helvella corium species aggregate in the Nordic countries. To achieve this, we used morphology and phylogenetic evidence from five loci – heat shock protein 90 (hsp), translation elongation factor 1-alpha (tef), RNA polymerase II (rpb2), and the 5.8S and large subunit (LSU) of the nuclear ribosomal DNA. All specimens under the name Helvella corium in the larger university fungaria of Norway, Sweden and Denmark were examined and barcoded, using partial hsp and/or rpb2 as the preferential secondary barcodes in Helvella. Additional fresh specimens were collected in three years (2015–2018) to obtain in vivo morphological data to aid in species discrimination. The H. corium species aggregate consists of seven phylogenetically distinct species, nested in three divergent lineages, i.e. H. corium, H. alpina and H. pseudoalpina sp. nov. in the /alpina-corium lineage, H. alpestris, H. macrosperma and H. nannfeldtii in the /alpestris-nannfeldtii lineage, and H. alpicola as a weakly supported sister to the /alpestris-nannfeldtii lineage. Among the seven species, the ribosomal loci expressed substantial variation in evolutionary rates, suggesting care in the use of these regions alone in delimitation of Helvella species. Altogether, 469 out of 496 available fungarium specimens were successfully barcoded

RPB2_HSP_LSU_alignment.fasta

Concatenated rpb2, hsp and lsu alignment used for ML and bayesian phylogenetic analyses. Fasta format. Rpb2 is bp 1-347, hsp is bp 348-616, lsu is bp 617-1314

RPB2_HSP_LSU_alignment.nex

Concatenated rpb2, hsp and lsu alignment used for ML and bayesian phylogenetic analyses. Nexus format. Rpb2 is bp 1-347, hsp is bp 348-616, lsu is bp 617-1314

The genera Helvella and Dissingia (Ascomycota: Pezizomycetes) in Europe – Notes on species from Spain

Phylogenetic analyses of 115 newly collected Helvella specimens from Spain using three genetic markers [heat shock protein 90 ( hsp ), RNA polymerase II second largest subunit ( rpb2 ) and the nuclear large subunit ribosomal DNA (LSU)] confirm the assignment of the Spanish collections to one Dissingia and 30 Helvella species. The analyses were supplemented with an additional sample of 65 Spanish and extralimital Helvella specimens from the fungaria of Oslo (O), Trondheim (TRH), Copenhagen (C), Uppsala (UPS), Stockholm (S) and Venice (MCVE). Nine species are described as new, i.e. Helvella fuscolacunosa, H. hispanica, H. iberica, H. inexpectata, H. neopallescens, H. phlebophoroides, H. poculiformis , H. retinervis , and H. terricola . We present photographs of a selection of fresh specimens and provide descriptions of all species of this diverse South European Mediterranean element of the genera in Europe