Phylogeography of Infraspecific Differentiation of Hydrangea serrata (Hydrangeaceae), a Widespread Shrub Species in the Japanese Archipelago

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Air-Stable Cyclohexasulfur as Cocrystal

A new stable cyclohexasulfur (cyclo-S₆) was discovered in the crystal of 3,5-diphenyl-1,2,4-dithiazol-1-ium (dpdti); dpdti was synthesized via an oxidation reaction of thiobenzamide with iodine in benzene, under reflux. Two kinds of crystal habitsbrick-shaped (crystal-<b>A</b>) and needle-shaped (crystal-<b>B</b>)were obtained following recrystallization from acetonitrile solvent. Single-crystal structure analysis using synchrotron X-ray radiation showed that both crystal-<b>A</b> and -<b>B</b> consist of a dpdti cation and an iodine anion. Furthermore, neutral cyclo-S₆ molecules are present in crystal-<b>A</b> as cocrystals, enclosed by the dpdti cation and the iodide anion. This is akin to cyclosulfur of <i>S</i>_<i>n</i> in zeolites and sodalities, suggesting a contribution to the stabilization of cyclo-S₆ molecules. The results show that crystal engineering of cocrystals may be used as a method to control the stability and activity of sulfur, for improved utilization

Multilocus coalescent species delimitation to evaluate traditionally defined morphotypes in Hydrangea sect. Asperae (Hydrangeaceae)

"The number of species recognized in section Asperae of the flowering plant genus Hydrangea differs widely between subsequent revisions. This variation is largely centered around the H. aspera species complex, with numbers of recognized species varying from one to nearly a dozen. Despite indications of molecular variation in this complex, no sequence-based species delimitation methods have been employed to evaluate the primarily morphology-based species boundaries. In the present study, a multi-locus coalescent-based approach to species delimitation is employed in order to identify separate evolutionary lines within H. sect. Asperae, using four chloroplast and four nuclear molecular markers. Eight lineages were recovered within the focal group, of which five correspond with named morphotypes. The other three lineages illustrate types of conflict between molecular species delimitation and traditional morphology-based taxonomy. One molecular lineage comprises two named morphotypes, which possibly diverged recently enough to not have developed sufficient molecular divergence. A second conflict is found in H. strigosa. This morphotype is recovered as a separate lineage when occurring in geographic isolation, but when occurring in sympatry with two other morphotypes (H. aspera and H. robusta), the coalescent species delimitation lumps these taxa into a single putative species.