Despite being one of the larger genera of Caryophyllaceae with about 60 cushion‐forming subshrubby species, Acanthophyllum is represented poorly in previous molecular phylogenetic studies. The genus is an important component of the subalpine steppe flora in Central to Southwest Asia. Although the placement of Acanthophyllum in the tribe Caryophylleae and a close relationship to Allochrusa has already been suggested, the monophyly of the genus and its infrageneric taxa, as well as its relation to other closely related genera, have not been addressed. We have assembled datasets of nuclear ribosomal internal transcribed spacer (ITS) sequences and intron sequences of the chloroplast gene rps16 for 47 Acanthophyllum species and 63 species of 11 additional genera from Caryophylleae. Phylogenetic analyses were performed using maximum parsimony, maximum likelihood and Bayesian methods. Our analysis suggests that Allochrusa, Diaphanoptera, Ochotonophila and Scleranthopsis are nested within Acanthophyllum but that the traditionally recognized sections of Acanthophyllum are monophyletic after reassignment of a few species. Emarginate petals may be a synapomorphy for one of the two basal clades of Acanthophyllum. Moreover, non‐monophyly of the genera Gypsophila and Diaphanoptera is suggested by the present study. The age of the crown clade of Acanthophyllum s.l. is estimated to be 11.1 Ma by *BEAST species tree analysis.

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In order to examine the systematic application of seed-coat micro-morphology in Gypsophila and allied genera, seed surfaces of 30 species and two varieties representing four genera of tribe Caryophylleae were examined with scanning electron microscope. The seeds of examined species range between 0.5Á2.1 mm in length and 0.3Á2.4 mm in diameter. The exomorphology of the seed coat shows two distinctive cell patterns. The epidermis is constructed either of elongated polygonal or of broad polygonal cells. The elongated type is the most common among the studied species, but the variation in alignment of testa cells, their size and shape as well as the density of protuberances may provide further information and useful diagnostic characters at generic and specific rank. The testa cells in Gypsophila and Saponaria are shallowly undulate, deeply undulate, lobed and armed at anticlinal walls. Deeply undulate anticlinal walls were observed in both Gypsophila and Ankyropetalum and a few species of Saponaria. Non-or indistinctly grooved anticlinal walls is the more common type in Allochrusa. Seed-coat characters support the separation of Gypsophila and Saponaria to some extent but disagree with recognition of Ankyropetalum as a genus separate from Gypsophila.

Nucleotide sequences from the internal transcribed spacers (ITS) of nuclear ribosomal DNA and 5.8S gene were used to infer the phylogeny of Tilia species (represented by 13 distinct populations) growing in different geographical areas of Hyrcanian forests in northern Iran. Four well-supported lineages were revealed, including that of a new species, T. hyrcana, with stellate trichomes on both sides of the leaves and petiole. T. hyrcana is a wellsupported cladospecies, with the ITS sequence and secondary structure following the diagnosable phylogenetic species concept, and is also characterized by a distinct morphology. A controversial species is Tilia rubra subsp. caucasica, with three different forms-an assemblage of taxa characterized by a lack of stellate trichomes on leaves-while Tilia begonifolia is distinguished by stellate trichomes on the underside of both leaves and petiole. The fourth lineage group, T. dastyla, is characterized by the presence of trichomes on the style. A single taxon found in the west of the Hyrcanian forest region is similar to T. begonifolia, but due to the former being located in a distinct group, a reassessment of the diagnostic morphology is recommended. ITS sequence data also suggested a closer relationship between T. rubra and T. begonifolia. Compensatory base change analysis was not strong enough to separate individual species within the Tilia genus. In general, the study supports the utility of ITS sequence data and secondary structure as accessory taxonomic characteristics with which to help clarify the systematics of the Tilia genus.

Acantholimon is an important component of the subalpine steppe flora in the Irano-Turanian region and the second largest genus of Plumbaginaceae with c. 200 cushion-forming subshrubby species. Because the genus has been poorly represented in previous phylogenetic studies, questions regarding its monophyly, phylogenetic relationships and infrageneric classification have not been addressed in a solid evolutionary framework. We used sequences from the nuclear ribosomal internal transcribed spacers and the plastid trnY (GUA) -trnT (GGU) intergenic spacer for 197 accessions of Acantholimon and nine putatively closely related Asian genera in Limonioideae. Contrary to previous results, Bayesian, maximum likelihood and maximum parsimony analyses show that Acantholimon is not monophyletic unless its limits are extended to include species currently placed in eight of these Asian genera. As circumscribed, the new Acantholimon s.l. is sister to Goniolimon and includes the following genera: Bamiania, Bukiniczia, Chaetolimon, Cephalorhizum, Dictyolimon, Gladiolimon, Popoviolimon and Vassilczenkoa. Our phylogenetic analyses also challenge the existing classification at the generic and infrageneric levels. A maximum likelihood reconstruction of ancestral states for morphological characters illustrates the possible scenarios by which the cushion architecture combined with linear acuminate leaves, also present in other steppic Irano-Turanian elements, were acquired in this group of Plumbaginaceae. Our study shows the importance of extensive taxon sampling for phylogenetic reconstruction of species-rich lineages.ADDITIONAL KEYWORDS: Irano-Turanian region -ITS -molecular phylogenetic analysis -morphological character evolution -plastid trnY-T.