Using isozyme analysis, we studied the genetic diversity among 316 Bromus hordeaceus (Poaceae) accessions of different geographic origin and belonging to five subspecies. Eight putative isozyme loci revealed remarkable allozyme variation. The isozyme variation occurred as different fixed homozygous and heterozygous phenotypes without segregation among the seed progeny. We detected no subspecies-specific allozymes. Two isozymes tend to differentiate among subspecies, indicating that subspecies of B. hordeaceus are still undergoing contemporary process of divergence. The differentiation into 65 multilocus isozyme lineages (MLILs) was not related to the geographic origin of B. hordeaceus accessions. Bromus hordeaceus did not lose genetic variation towards its range margins: we found 7.7% out of total MLILs in the northernmost part of a core distribution range and 7.7%–40% in the southern part. We recorded silencing of one homeoallelic isozyme gene in the allotetraploid genome of B. hordeaceus for accessions of different geographic origins.

Microsporogenesis and male gametogenesis in Psammosilene tunicoides (Caryophyllaceae) were studied and described for the first time. This species possesses essential embryological features of Caryophyllaceae, such as tetrasporangiate anthers, fibrous endothecium, glandular tapetum, two tapetal cells, simultaneous cytokinesis of pollen mother cells, and three-celled pollen grains. A majority of the microspores were arranged in tetrahedral tetrads, but rhomboidal tetrads were observed in one population. Notable differences in the tapetum degeneration were observed in different populations. Early or late degeneration may both lead to male sterility and subsequently to reproductive failure. The tapetum was dimorphic in two populations. We also included data concerning the breeding system of the species and discussed its implications for conservation purposes.

Veronica hederifolia (Plantaginaceae) — an invasive, alien weed in eastern China — is of great concern due to its potential to spread. This study was conducted to determine the genetic diversity of V. hederifolia in comparison with several congeneric species, including V. persica, V. arvensis, V. didyma and V. peregrina as outgroups, using the Amplified Fragment Length Polymorphism (AFLP) technique. The samples of V. hederifolia were collected from 24 locations in Nanjing and Zhoushan, and genomic DNA was digested with the enzymes EcoRI/MseI and amplified with six E 3/M 3 primer combinations. Both mono- and polymorphic AFLP markers were analyzed to estimate genetic diversity of V. hederifolia based on a range of standard indicators. A high percentage of polymorphic bands (89.23%) existed in the populations examined, implying high genetic diversity. Based on all genetic indices, the Nanjing population, which was the first reported in China, exhibited greater genetic diversity than the Zhoushan population. Substantial variation was also found among individual plants collected from a single site near Nanjing, with 79.56% polymorphism. This high genetic diversity indicates this weed species potentially has broad adaptability. Cluster analysis of AFLP data placed V. hederifolia samples into three groups depending largely on geographical locations.

Leaf trichomes can protect plants against herbivory and drought, but can be costly to produce. Theory suggests that selection for reduced costs of resistance may result in the evolution of inducible defences. We quantified variation in tolerance to drought and defoliation, and tested the hypotheses that (a) tolerance is associated with cost, (b) leaf trichome production increases tolerance to drought, and (c) trichome production is increased in response to defoliation and drought stress in Arabidopsis lyrata (Brassicaceae). Eight maternal half-sib families were exposed to two watering regimes and four defoliation treatments in a factorial design. Tolerance to drought varied among families and was inversely related to leaf size, but was not related to trichome density. Family mean performance in the low-watering treatment tended to correlate negatively with that in the control treatment. Trichome production was not induced by defoliation or drought stress. The results suggest that there is genetic variation in tolerance to drought in the study population, that tolerance to drought is associated with a cost, and that trichome production does not increase tolerance to drought in A. lyrata.

The genus Diphyscium (Diphysciaceae, Bryophyta) has three species in the Hunan Province of China: D. fulvifolium Mitt., D. mucronifolium Mitt, and D. chiapense D.H. Norris subsp. unipapillosum (Deguchi) T.-Y. Chiang & S.-H. Lin. Diphyscium fulvifolium is clearly the most common species. The other two taxa are reported for the first time from Hunan, and D. chiapense subsp. unipapillosum also from Jiangxi; in China, it was previously known only from Taiwan. The three species are illustrated in line drawings. A previous record of D. foliosum (Hedw.) Mohr was based on a misidentified specimen and the species is thus excluded from the flora of Hunan.

Three new species of the orchid genus Pachygenium are described and illustrated: Pachygenium schmidtianum Mytnik, Szlach. & Górniak, P. triangulare Mytnik, Szlach. & Górniak and P. arechavaletae Mytnik, Szlach. & Górniak. A new combination on the species level, Pachygenium callosum (M.N. Correa) Mytnik, Szlach. & Górniak is validated. The taxonomic position of the new taxa is briefly discussed. Pachygenium is compared in a table with Pelexia on the generic level. A brief taxonomic history of Pachygenium is presented.

Chirita auriculata J.M. Li & S.X. Zhu sp. nova (Gesneriaceae) is described from Yunnan, China, and illustrated. We investigated its phylogenetic relationships within the Chirita-Chiritopsis group using separate and combined data from the nuclear ribosomal Internal Transcribed Spacer (ITS) and the chloroplast trnL-F sequence for twenty-three species in different sections of Chirita and Chiritopsis. Chirita auriculata belongs to section Chirita. This is an unexpected phylogenetic position because the new species has a calyx divided almost to the base, ovoid ovaries shorter than the styles, small plant bodies, and small flowers, characters that typically define Chiritopsis. Its position close to C. pumila is supported by its annual stems and membranous leaves.

Epimedium pudingense S.Z. He, Y.Y. Wang & B.L. Guo (Berberidaceae), a new species from Guizhou, SW China, is described and illustrated. It is similar to E. sagittotum in its nodose rhizome, two opposite ternate leaves and saccate petals, but differs by the size and shape of the four inner sepals and by the leaves pilose or glabrous on the abaxial surface.

Elatostema cataractum L.D. Duan & Q. Lin (Urticaceae), a new species from Libo county, Guizhou province, China, is described and illustrated. The relationship among this species and its morphological siblings are discussed.

Onobrychis bakuensis Ranjbar, Vitek & Karamian sp. nova (Fabaceae), endemic to Azerbaijan, is described and illustrated. It belongs to the subgenus Sisyrosema section Hymenobrychis. It is distributed in northwestern Iran, and west of the Caspian Sea in Azerbaijan. It is morphologically close to O. kachetica, but is easily distinguished by the black indumentum of its rachis, leaflets, peduncle, calyx and standard.

Hedychium longipetalum X. Hu & N. Liu sp. nova (Zingiberaceae), from Yunnan Province, China, is described and illustrated. It resembles H. yunnanense, but differs from that species in the number of flowers per bract, in the form of the labellum, and in the length of the petal lobes.