1,720,974 research outputs found
Rediscovery of Crocus biflorus var. estriatus (Iridaceae) and its taxonomic characterisation
Full text linkThe Italian endemic Crocus biflorus usually shows white or lilac flowers with three-to-five striking violet
longitudinal stripes on the outer tepals, but unstriped plants were recorded in the past. These plants were
originally described as C. annulatus subvar. estriatus, and subsequently recombined as a variety of C. biflorus.
The rediscovery of such plants in Toscana gave us the opportunity to clarify their systematic relationships,
so that we typified the name, and performed karyological and ITS analyses. These plants share the
same chromosome number (2n = 2x = 8) and ITS sequence with C. biflorus s. str
New light on phylogeny and taxonomy of the Eurasian Gagea villosa-G. fragifera complex (Liliaceae)
No full textPhylogenetic analysis shed new light into taxonomy and reticulate evolution of the critical Mediterranean Gagea sect. Didymobulbos (Liliaceae)
No full textNeotypification of the name Crocus biflorus Mill. (Iridaceae) and its consequences in the taxonomy of the genus
No full textRecent phylogenetic investigations on the genus Crocus proved several infra-generic units predominantly within section Nudiscapus
to be para- or polyphyletic even at infra-specific level. In particular, the 23 “subspecies” of C. biflorus Mill. turned
out to be a polyphyletic assemblage grouping in very different clades and sub-groups. In addition, they were established under
the binomial Crocus biflorus, not yet typified. As first step, we neotypified this name. Then, through a phylogeny based
on the ETS region of the nuclear ribosomal (nr) DNA as an additional nuclear marker to the already available nrITS region,
we further demonstrated that all the “subspecies” represent independent evolutionary lineages. Therefore, all these taxa are
treated here at species level. To achieve this, 10 new combinations are proposed
Reticulate evolution of the critical Mediterranean Gagea sect. Didymobulbos (Liliaceae), and its taxonomic implications
No full text
A pre‐Miocene Irano‐Turanian cradle: Origin and diversification of the species‐rich monocot genus Gagea (Liliaceae)
Full text linkAbstract The Irano‐Turanian (IT) floristic region is considered an important center of origin for many taxa. However, there is a lack of studies dealing with typical IT genera that also occur in neighboring areas. The species‐rich monocot genus Gagea Salisb. shows a center of diversity in IT region and a distribution in adjacent regions, therefore representing a good study object to investigate spatial and temporal relationships among IT region and its neighboring areas (East Asia, Euro‐Siberia, Himalaya, and Mediterranean). We aimed at (a) testing the origin of the genus and of its major lineages in the IT region, (b) reconstructing divergence times, and (c) reconstructing colonization events. To address these problems, sequences of the ribosomal DNA internal transcribed spacer (ITS) region of 418 individuals and chloroplast intergenic spacers sequences (psbA‐trnH, trnL‐trnF) of 497 individuals, representing 116 species from all sections of the genus and nearly its entire distribution area were analyzed. Divergence times were estimated under a random molecular clock based on nrITS phylogeny, which was the most complete data set regarding the representation of species and distribution areas. Ancestral distribution ranges were estimated for the nrITS data set as well as for a combined data set, revealing that Gagea most likely originated in southwestern Asia. This genus first diversified there starting in the Early Miocene. In the Middle Miocene, Gagea migrated to the Mediterranean and to East Asia, while migration into Euro‐Siberia took place in the Late Miocene. During the Pleistocene, the Arctic was colonized and Gagea serotina, the most widespread species, reached North America. The Mediterranean basin was colonized multiple times from southwestern Asia or Euro‐Siberia. Most of the currently existing species originated during the last 3 Ma
Phylogeny, karyotype evolution and taxonomy of Crocus ser. Verni (Iridaceae)
No full textThe taxonomically complicated Crocus series Verni is characterized by high intra-and interspecific variability of karyotypes (2n = 8-23). With the aim to get more insights into complex karyotype evolution and to clarify the taxonomy of this group, we combined morphological (twelve characters), molecular (chloroplast DNA: trnL-trnF, ndhF; nuclear DNA: ITS, pCOSAt103) and karyological analyses. Samples of different populations of C. etruscus, C. ilvensis, C. kosaninii, C. tommasinianus, C. vernus sensu lato and C. longiflorus (series Longiflori) were analyzed. Quantitative karyotype parameters were calculated for all taxa involved based on the available literature. For the taxon traditionally known as C. vernus, the analyses suggest that it should be split in five species: C. heuffelianus, C. neapolitanus, C. neglectus sp. nov., C. siculus and C. vernus. The comparison of genome total haploid lengths suggests that in the evolution of the group polyploidization only played a role within the C. vernus species complex, where we also detected two hybridization events. In all other taxa, chromosome evolution is probably characterized by chromosome fusions and fissions, sometimes affecting the entire haploid chromosome set. Comparative cytogenetics of the group indicates that series Verni is subject to a peculiar type of unequal change in chromosome size, i.e., that not both chromosome arms gain or lose equally in DNA content. As a taxonomic consequence of our study, series Verni is newly circumscribed, now including the autumn-flowering C. longiflorus and excluding C. baytopiorum
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