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This study examines phylogenetic relationships among the 12 genera of Urticeae (Urticaceae) and investigates the pattern of morphological evolution based on analysis of nuclear ribosomal internal transcribed spacer (nrlTS) and two plastid DNA regions (rbcL exon, trnL-F spacer). Sequence data were analyzed using maximum parsimony and Bayesian inference, and selected morphological traits were mapped onto the molecular tree. The molecular results strongly supported monophyly of Urticeae, excluding Gyrotaenia, which is related to Elatostemateae. All genera were monophyletic except for Urtica, Laportea, and Urera. Two Hesperocnide species are nested within Urtica. Laportea and Urera are divided into three groups with a strong geographical signal. The inferred phylogeny indicates five well-supported clades in Urticeae: clade A including Urtica (with Hesperocnide), Zhengyia, Laportea I, and Nanocnide\ clade B comprising Dendrocnide and Discocnide\ clade C including only Girardinia; clade D including Laportea II; and clade E including Obetia, Urera I, II, III, and Poikilospermum. Although it is difficult to identify morphological synapomorphies for these well - defined clades within Urticeae, character analysis shows that the herbaceous habit and alternate leaves are the ancestral states in the tribe. The presence of stinging hairs is the derived status in Urticeae, and it might have been a key innovation triggering species diversificati on in the tribe. [ABSTRACT FROM AUTHOR]

It has been suggested that many plants now found in the arctic originated from ancestors that occurred at high altitudes in the southern mountains of the Northern Hemisphere during the Tertiary. However, this hypothesis has rarely been tested using a molecular phylogenetic approach. Here, we present a fossil-calibrated molecular phylogeny of Lagotis, an arctic-alpine genus with the greatest diversity in the Qinghai-Tibetan Plateau (QTP) and Central Asian mountains, based on five chloroplast (matK, psbA-trnH, rpslô, trnG-S, trnL-F) and nuclear ribosomal ITS DNA markers. Within this framework, we infer the ancestral area and biogeographic history of the genus. Four major clades (A-D) within Lagotis were recovered with strong support, which largely correspond to the previous classification of the genus. Within clade A, Lagotis species from QTP were distributed among several subclades, and L. integrifolia from Central Asia was sister to L. glauca and L. minor from the arctic and subarctic region. The Bayesian molecular dating and the ancestral area reconstruction analyses suggested that Lagotis could have originated in the QTP in the Miocene (Tertiary), and that the genus radiated from the Miocene to Pleistocene. The diversification of Lagotis probably took place predominantly in the QTP and it subsequently spread to the Central Asian high-lands, followed by northward migration into the arctic. Our results support the hypothesis that the "Central Asiatic Highland Corridor" as an important route for the migration of the flora between the arctic and QTP. [ABSTRACT FROM AUTHOR]

Species identification and analysis of phylogenetic relationships within the genus Typha are difficult because of the high degree of variability among morphological characters and frequent interspecific hybridization. Traditionally, two sections (T. sect. Ebracteolatae and sect. Bracteolatae) have been recognized within the genus based on the presence or absence of bracteoles in the female flowers. The aims of this study were to reconstruct the phylogeny of Typha using DNA sequence data from nuclear LEAFYand three plastid regions, and to evaluate previous classifications. We sampled nine species from various regions that were each invariant at the molecular level. A parsimony consensus tree recovered three clades in the genus: clade I including T. angustifolia, T. elephantina, T. domingensis, and T. capensis; clade II including T. orientalis and T. laxmanni; and clade III comprising T. latifolia and T. shuttleworthii. Typha minima was found sister to the rest of the Typha species with maximal bootstrap support. The results do not support previous classifications of Typha. Character analysis showed that bracteole loss, spatulate stigma, lack of a gap between staminate and pistillate inflorescences, and monad pollen are derived characteristics in Typha. [ABSTRACT FROM AUTHOR]

Premise of the study: Two marker systems were developed for the molecular identifi cation of three Trapa species based on the length variation of nuclear AP2 and trnL-F chloroplast intergenic spacer region. • Methods and Results: Our marker systems analyzed 118 individuals among 36 populations from three Trapa species. Trapa incisa was found to have a unique genotype from the other two species. Individuals of T. bispinosa were distinguished from T. japonica because the former had only a single AP2 genotype. Moreover, our results suggest a hybrid status of T. japonica in terms of two bands within an individual. One band was specifi c to T. japonica and the other one shared with T. bispinosa . • Conclusions: Our marker system demonstrates that nucleotide sequence variations can serve as a fast, reliable, and reproducible tool for molecular genotyping and examining the natural hybrid of water chestnut species. [ABSTRACT FROM AUTHOR]

Polyploidy plays an important role in the speciation of Isoëtes. Increasing our knowledge about the specific origin of each polyploid or phylogenetic relationship among species has been hampered because of conserved morphological variation and scarce habitats. We present several hypotheses concerning the speciation pathways of Isoëtes species distributed in East Asia. Our hypotheses are inferred from phylogenetic relationships that were elucidated using sequences of the internal transcribed spacer regions of nuclear ribosomal DNA, a second intron of LEAFY, and chloroplast DNA trnS-psbC spacer regions. These inferred phylogenetic relationships indicated that (1) the Chinese tetraploid, I. sinensis, is closely related to I. yunguiensis; (2) the Korean endemic species, I. hallasanensis, is an autotetraploid derived from I. taiwanensis or closely related taxa; (3) the hexaploid I. coreana forms a clade and has its closest evolutionary relationships with I. taiwanensis or I. hallasanensis; and (4) the Japanese hexaploid I. japonica is closely related to I. taiwanensis-I. coreana and I. sinensis-I. yunguiensis. These results suggest that inter-specific hybridization and polyploidization have played central roles in speciation of East Asian Isoëtes. Furthermore, I. taiwanensis, an endemic species in Taiwan, has been involved in at least three cases of autopolyploid or allopolyploid speciation in East Asia. [ABSTRACT FROM AUTHOR]