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The new genus and species Pulvinatusia xuegulaensis (Brassicaceae) are described and illustrated. The species is a cushion plant collected from Xuegu La, Xizang, China. Its vegetative parts are most similar to those of Arenaria bryophylla (Caryophyllaceae) co-occurring in the same region, while its leaves and fruits closely resemble those of Xerodraba patagonica (Brassicaceae) from Patagonian Argentina and Chile. Family-level phylogenetic analyses based on both nuclear ITS and plastome revealed that it is a member of the tribe Crucihimalayeae, but the infra-/intergeneric relationships within the tribe are yet to be resolved.

Salweenia (Leguminosae) has long been defined as a monotypic genus. In this study we carried out comprehensive studies on populations of S. wardii Baker f. across its distribution range. The results showed that this species diverged into two distinct groups: plants from the Yalong Jiang valley have linear leaflets 0.07-0.14 cm wide and relatively flattened legumes, as well as a 2A karyotype asymmetry, whereas plants from the Nu Jiang and Lancang Jiang drainages have lanceolate leaflets 0.20-0.34 cm wide, undulant legumes, and a 1A karyotype asymmetry. Furthermore, molecular phylogenetic analysis of four chloroplast DNA markers (trnL-F rpl32-trnL, psbA -trnH, trnS-G) recovered two reciprocally monophyletic clades among accessions of plants from these two areas respectively. We therefore recognize individuals of S. wardii in the Yalong Jiang valley as a separate species, S. bouffordiana sp.nov. Salweenia thus contains two allopatrically distributed species and the genus is no longer monotypic. The origin of the disjunction between the two species is briefly discussed and it is hypothesized to have come about through vicariance, resulting of several historic river separations, reversal and capture events estimated to have taken place during the Pleistocene. [ABSTRACT FROM AUTHOR]

Cytological studies were carried out on eight species of five genera (Anisodus,Atropanthe,Hyoscyamus,MandragoraandPrzewalskia) in the tribe Hyoscyameae (Solanaceae). First chromosome counts were reported in six species:Anisodus luridus,A. acutangulus,A. tanguticus,A. carniolicoides,Atropanthe sinensisandMandragora caulescens, all with 2n = 8x = 48. Two records, forHyoscyamus niger(2n = 2x = 34) andPrzewalskia tangutica(2n = 4x = 44), were also confirmed. All species studied showed the proximal type of mitotic prophase chromosome condensation pattern. Three types of interphase nuclei were recognized: the round prochromosome type forAnisodus,AtropantheandMandragora, the rod prochromosome type forPrzewalskiaand the complex chromocentre type forHyoscyamus. The cytological data supported the close relationship of all four species ofAnisodus. Evidence from the interphase nuclei and chromosome base numbers supported the traditional classification of Hyoscyameae into two groups, i.e.Physochlaina praealta+ Hyoscyamus(complex interphase type andx = 7, 14, 17) andPrzewalskia+ Atropanthe+ Anisodus+ Scopolia+ Atropa+ Mandragora(prochromosome type andx = 6, 11). Polyploidy is found in most species of the tribe in the Himalayan–Hengduan Mountains, as well as in the Mediterranean region, west–central Asia and eastern Asia. It seems that it probably occurred very early in Hyoscyameae evolution, before the uplift of the Himalayan–Hengduan Mountains. The Himalayan orogeny might have played a minor role in the polyploid evolution of plants in this tribe. © 2005 The Linnean Society of London.Botanical Journal of the Linnean Society, 2005,147, 457–468. [ABSTRACT FROM AUTHOR]