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Taxus is a genus of trees and shrubs with high value in horticulture and medicine as a source of the anticancer drug paclitaxel. The taxonomy of the group is complex due to the lack of diagnostic morphological characters and the high degree of similarity among species. Taxus has a wide global geographic distribution and some taxonomists recognize only a single species with geographically defined subgroups, whereas others have described several species. To address these differences in taxonomic circumscription, phylogenetic analyses were conducted on DNA sequences using Maximum Likelihood, Bayesian Inference and TCS haplotype networks on single and combined gene regions obtained for the nuclear ribosomal ITS region and the plastid trnL intron and trnL-F intergenic spacer. Evidence is presented for the sister group status of Pseudotaxus to Taxus and the inclusion of Amentotaxus, Austrotaxus, Cephalotaxus and Torreya within Taxaceae. Results are consistent with the taxonomic recognition of nine species: T. baccata, T. brevifolia, T. canadensis, T. cuspidata, T. floridana, T. fuana, T. globosa, T. sumatrana and T. wallichiana, but evidence is found for less species distinction and considerable reticulation within the T. baccata, T. canadensis and T. cuspidata group. We compare the results to known taxonomy, biogeography, present new leaf anatomical data and discuss the origins of the hybrids T. Xmedia and T. Xhunnewelliana. [ABSTRACT FROM AUTHOR]

A new bicarpellate Buxus species, Buxus sirindhorniana W. K. Soh, M. von Sternburg, Hodk.. J. Parn., is described from northern Thailand. This is the first reported bicarpellate species of Buxus. The pollen morphology and the degree of pollen viability of the species are reported. DNA was extracted from herbarium samples and the internal transcribed spacer (ITS) region of nuclear ribosomal DNA sequenced. The palynological evidence and the phylogenetic reconstruction support the contention that this new species belongs to the genus Buxus. The morphological diversity of reproductive organs in the Buxaceae, in relation to this new species, is briefly discussed. [ABSTRACT FROM AUTHOR]

C4 photosynthesis is a series of anatomical and biochemical modifications to the typical C3 pathway that increases the productivity of plants in warm, sunny, and dry conditions. Despite its complexity, it evolved more than 62 times independently in flowering plants. However, C4 origins are absent from most plant lineages and clustered in others, suggesting that some characteristics increase C4 evolvability in certain phylogenetic groups. The C4 trait has evolved 22-24 times in grasses, and all origins occurred within the PACMAD clade, whereas the similarly sized BEP clade contains only C3 taxa. Here, multiple foliar anatomy traits of 157 species from both BEP and PACMAD clades are quantified and analyzed in a phylogenetic framework. Statistical modeling indicates that C4 evolvability strongly increases when the proportion of vascular bundle sheath (BS) tissue is higher than 15%, which results from a combination of short distance between BS and large BS cells. A reduction in the distance between BS occurred before the split of the BEP and PACMAD clades, but a decrease in BS cell size later occurred in BEP taxa. Therefore, when environmental changes promoted C4 evolution, suitable anatomy was present only in members of the PACMAD clade, explaining the clustering of C4 origins in this lineage. These results show that key alterations of foliar anatomy occurring in a C3 context and preceding the emergence of the C4 syndrome by millions of years facilitated the repeated evolution of one of the most successful physiological innovations in angiosperm history. [ABSTRACT FROM AUTHOR]

The taxonomy of Bambusoideae is in a state of flux and phylogenetic studies are required to help resolve systematic issues. Over 60 taxa, representing all subtribes of Bambuseae and related non-bambusoid grasses were sampled. A combined analysis of five plastid DNA regions, trnL intron, trnL-F intergenic spacer, atpB-rbcL intergenic spacer, rps16 intron, and matK, was used to study the phylogenetic relationships among the bamboos in general and the woody bamboos in particular. Within the BEP clade (Bambusoideae s.s., Ehrhartoideae, Pooideae), Pooideae were resolved as sister to Bambusoideae s.s. Tribe Bambuseae, the woody bamboos, as currently recognized were not monophyletic because Olyreae, the herbaceous bamboos, were sister to tropical Bambuseae. Temperate Bambuseae were sister to the group consisting of tropical Bambuseae and Olyreae. Thus, the temperate Bambuseae would be better treated as their own tribe Arundinarieae than as a subgroup of Bambuseae. Within the tropical Bambuseae, neotropical Bambuseae were sister to the palaeotropical and Austral Bambuseae. In addition, Melocanninae were found to be sister to the remaining palaeotropical and Austral Bambuseae. We discuss phylogenetic and morphological patterns of diversification and interpret them in a biogeographic context. [ABSTRACT FROM AUTHOR]

• Background and Aims Representatives from Papaver, Roemeria, Stylomecon and Meconopsis were studied to elucidate phylogenetic relationships between Papaver and these closely allied genera.• Methods Two molecular data sets were used individually and combined and included sequences from the internally transcribed spacer region (ITS) of 18S–26S nuclear ribosomal DNA and the trnL intron and the trnL–trnF intergenic spacer region of plastid DNA.• Key Results Parsimony analysis demonstrated that the genus is not monophyletic unless the closely related Roemeria, Stylomecon and Meconopsis cambrica are included in a revised circumscription of Papaver. Three distinct clades are resolved in a combined ITS and trnL–F analysis. Clade 1 consists of Papaver sect. Meconella and Asian Meconopsis. Clade 2 contains a group here identified as Papaver s.s., comprising sections Carinatae, Meconidium, Oxytona, Papaver, Pilosa, Pseudopilosa and Rhoeadium. Clade 3 consists of Papaver sect. Argemonidium and Roemeria refracta. A number of diagnostic indels support these groupings. Within clade 2, sects. Papaver and Rhoeadium are either not monophyletic or lack evidence supporting their monophyly.• Conclusions The results of this molecular analysis indicate that a number of morphological characters such as valvate capsule dehiscence, dark or light filaments and sessile stigmatic discs have arisen in parallel. The phylogenetic trees are incongruent with the existing taxonomy of Papaver, and a revised classification is suggested. [ABSTRACT FROM AUTHOR]

Cyperaceae are the third largest monocotyledon family, with considerable economic and conservation importance. In subfamily Mapanioideae there is particular specialization of the inflorescence into units termed spicoids. The structural homology of the spicoid is difficult to interpret, making determination of intrafamilial relationships problematic. To address this, pollen from eight species in Mapanioideae was investigated using light microscopy and scanning and transmission electron microscopy. Pollen development was also examined to identify the type of pollen present in these species. We also analyzed DNA sequence data using the trnL-F and rps16 regions from 25 genera and 35 species of Cyperaceae, Juncaceae, and Thurniaceae. Two types of pollen, Mapania-type and pseudomonad, were identified. Analysis of combined DNA and pollen data resolved a clade sister to the rest of Cyperaceae, corresponding to Mapanioideae. Within this, two further clades were resolved. One comprised taxa assigned to tribe Hypolytreae, which had Mapania-type pollen. The other comprised taxa mainly assigned to tribe Chrysitricheae, but included two taxa from Hypolytreae, Capitularina and Exocarya. All taxa in this clade had pseudomonad pollen. Thus new groupings within the subfamily have been discovered based on the specialization of some taxa in terms of their pollination biology. [ABSTRACT FROM AUTHOR]

The article evaluates phylogenetic relationships of 34 species and 11 out of 14 Vitaceae genera grape family using parsimony and Bayesian analyses of four plastid deoxyribonucleic acid (DNA) sequence regions. It informs that Vitaceae were shown to be monophyletic and well-supported groups at infrafamilial level. The article also mentions that parsimony-based studies of character evolution suggested that 5-merous flowers, and hermaphroditic sexuality are ancestral character states in the family.