A new complex [Cd(2,4-D)2(Im)2(H2O)2] with 2,4-dichlorophenoxyacetic acid (2,4-DH) and imidazole (Im) as ligands has been synthesized and characterized by elemental analysis, IR spectrometry and single-crystal X-ray diffraction. The Cd(II) atom is coordinated in a distorted octahedral geometry, which is defined by two O atoms from two monodentate 2,4-dichlorophenoxyacetate ligands, two N atoms from two imidazole ligands and two water molecules. Intermolecular O-H...O hydrogen bonds form chains, which are connected by N-H...O hydrogen bonds, generating a sheet structure. The molecules are further assembled by π...π stacking interactions to form a two dimensional supramolecular network.

The phylogenetic relationships of 15 taxa from Hystrix and the related genera Leymus (NsXm), Elymus (StH), Pseudoroegneria (St), Hordeum (H), Psathyrostachys (Ns), and Thinopyrum (E) were examined by using the Giemsa C-banded karyotype. The Hy. patula C-banding pattern was similar to those of Elymus species, whereas C-banding patterns of the other Hystrix species were similar to those of Leymus species. The results suggest high genetic diversity within Hystrix, and support treating Hy. patula as E. hystrix L., and transferring Hy. coreana, Hy. duthiei ssp. duthiei and Hy. duthiei ssp. longearistata to the genus Leymus. On comparing C-banding patterns of Elymus species with their diploid ancestors (Pseudoroegneria and Hordeum), there are indications that certain chromosomal re-arrangements had previously occurred in the St and H genomes. Furthermore, a comparison of the C-banding patterns of the Hystrix and Leymus species with the potential diploid progenitors (Psathyrostachys and Thinopyrum) suggests that Hy. coreana and some Leymus species are closely related to the Ns genome of Psathyrostachys, whereas Hy. duthiei ssp. duthiei, Hy. duthiei ssp. longearistata and some of the Leymus species have a close relationship with the E genome. The results suggest a multiple origin of the polyploid genera Hystrix and Leymus.