This study describes the tree vegetation and soils occurring in a seasonally dry tropical forest (SDTF) and mesotrophic cerradão transition in southwestern Brazil. All trees ≥ 5 cm diameter were measured in 20 plots of 20 × 25 m, 10 in SDTF, and 10 in mesotrophic cerradão. Ten soil samples of 0−20 cm depth were made per plot and mixed in plot groups to produce two composite samples. A total of 71 species was recorded. Anadenanthera colubrina had the highest importance values in both formations. Differences in soil fertility were found between SDTFs (eutrophic soils) and mesotrophic cerradão (mesotrophic soils). A non-metric multidimensional scaling and cluster analysis confirmed the soil fertility segregation, and also showed an agreement between soil fertility and variance in species composition gradients. The mesotrophic cerradão showed higher species richness since it also includes many species typical of more dystrophic and open forms of Cerrado.

Euphorbia sect. Tithymalopsis (Euphorbiaceae) comprises seven species of herbaceous perennials restricted to the south-eastern USA. The species of sect. Tithymalopsis are united and distinguished from other sections in Euphorbia by having a thick and cylindrical root system, a glabrous cyathium, five glands with petaloid appendages, one to three stems arising from the root, absence of vestigial sepals in pistillate flowers, rounded leaf apices, and pitted or smooth seeds without a caruncle. Cladistic analyses indicate that sect. Tithymalopsis consists of two subgroups: (1) E. corollata, E. discoidalis, E. pubentissima and E. polyphylla; and (2) E. curtisii, E. gracilior and E. mercurialina. Comparative data from vegetative morphology, pollen morphology, seed morphology, cytology, crossability, reproductive biology, habitat and distribution are presented. Keys and descriptions to the species are provided.

The shrubby, spiny, succulent species Euphorbia collenetteae D.Al-Zahrani & El-Karemy (Euphorbiaceae) from the southern Red Sea coast and islands is described and illustrated as new. Diagnostic characters, a description and taxonomic comments on the species are given. It is compared with the closely related Euphorbia fractiflexa S.Carter & J.R.I.Wood. The geographical distribution of the new species is shown.

Until recently the genus Didymocarpus Wall. (Gesneriaceae) was used in an unwarrantably wide sense and included more than 180 species. It has now been remodelled and restricted to around 70 species. Of these, 18 species and one variety are known to occur in Thailand. To clarify the relationships among Thai species of Didymocarpus we sequenced the internal transcribed spacers (ITS) of nuclear ribosomal DNA (nrDNA) from a sample of 23 taxa, including 15 from Thailand, four from China, three from Malaysia and one from Bhutan. Seventeen morphological characters were coded for all 23 taxa and optimized onto a retention index (RI) reweighted maximum parsimony (MP) tree. The phylogenetic analyses suggested that Didymocarpus taxa formed a strongly supported monophyletic clade, with several supported subclades. The combination of molecular phylogeny and optimization of morphological characters suggests the presence of three distinct groups: the first, corresponding to Didymocarpus sect. Elati Ridl., includes plants with tall stems, yellow or white flowers and one-celled conoid or two-celled headed pigment glands; the other two groups, which represent Didymocarpus sect. Didymocarpus, both contain plants with dwarfed stems and violet or purple flowers, but are distinguished by the presence of both four-celled conoid or onecelled globose glands in one, and the absence in the other. Optimization of geographical locality onto the phylogeny led us to propose the hypothesis that, based on this sample, the geographical origin of Didymocarpus is the Malay Peninsula, and the ancestral corolla colour is white/yellow. Subsequent dispersal northward through southern and northern Thailand to China and Bhutan was accompanied by the evolution of a purple/violet corolla colour.

The genus Donella Pierre ex Baill. is here reinstated and Austrogambeya Aubrév. is, for the first time, placed in synonymy based on the findings of recent combined molecular and morphological studies. Seventeen species are recognised, two of which, Donella ranirisonii L.Gaut. & Mackinder and D. humbertii Capuron ex Mackinder & L.Gaut., from Madagascar, are described here for the first time. The flowers of Donella ambrensis and D. delphinensis are described here for the first time, as are the fruits of D. guereliana. Two keys, to the species of Madagascar and tropical Africa, respectively, are presented. Ten species are endemic to Madagascar, six species are endemic to tropical Africa and one, Donella lanceolata, occurs from Madagascar to the Solomon Islands. For each species, the accepted name with synonymy is given, followed by a morphological description. Geographical range and details of habitat are provided, with taxonomic and/or nomenclatural notes as appropriate. Distribution maps are presented for all species, and preliminary conservation assessments are made. Five species qualify for a category of Threat, and three further species are assessed as Near Threatened. An index to species and a list of exsiccatae are included.

Didymocarpus rodgeri (incl. var. siamensis) is reduced to a synonym of D. aureoglandulosus (SE India, Burma and Thailand); D. subalternans var. curvicapsa (Nepal–Sikkim) is raised to specific rank, and a new species, D. triplotrichus (Darjeeling distr. and Sikkim), is described. Lysionotus himalayensis is redetermined and reduced to synonymy under L. serratus; as a result L. atropurpureus, which name it had recently superseded, is reinstated. Aeschynanthus kingii and A. levipes are both transferred to Lysionotus, while L. wardii and L. gracilipes are reduced to synonymy under L. pubescens. Notes and new records are provided for L. confertus and L. serratus var. pterocaulis.

A preliminary analysis of New Caledonian Araliaceae has shown varying degrees of support for previous hypotheses on sexual system evolution in the family. Andromonoecy, rather than hermaphroditism, is strongly supported as the ancestral sexual system for the Araliaceae. Derivation of hermaphroditism from andromonoecy in Delarbrea harmsii R. Vig. and Polyscias bracteata (R. Vig.) Lowry, ined. is also strongly supported. Support for the derivation of dioecy from andromonoecy in several New Caledonian species of Polyscias J. R. Forst. & G. Forst. depends in part on an assumption that andromonoecy cannot be secondarily derived from dioecy. The derivation of hermaphroditism from andromonoecy in Schefflera candelabra Baill. and S. pseudocandelabra R. Vig. is equivocal. The hypothesis that the immediate ancestors of Arthrophyllum Blume were andromonoecious is not supported.

A synopsis of Rivea Choisy (Convolvulaceae) accounts for all names published in the genus in a concise nomenclatural review. Three species are recognized; a key is provided to identify them. Excluded species are referred to the currently accepted names and an index of numbered specimens examined will allow curators to correctly name material in herbaria.

Two new species of Boraginaceae are described from Turkey: Paracaryum hedgei and Rindera dumanii. Their affinities and phytogeography are discussed. Both species are illustrated and their distributions mapped. Rindera sect. Bilegnum is raised to subgeneric rank as Rindera subgen. Bilegnum.

The genus Nageia has received varying taxonomic treatments. The most recent are those by de Laubenfels (1969, under the name Decussocarpus de Laub.; 1987, as Nageia Gaertn.), by Fu (1992) and by Melikyan & Bobrov (2000). De Laubenfels treated the genus in a broad sense, embracing three sections that are now generally recognized respectively as the separate genera Afrocarpus (J. Buchholz & N. E. Gray) Gaussen ex C. N. Page, Nageia sensu stricto, and Retrophyllum C. N. Page (as by Page, 1989, 1990). In de Laubenfels's earlier paper, these three sections were respectively called Decussocarpus de Laub. sect. Afrocarpus (J. Buchholz & N. E. Gray) de Laub., D. sect. Dammaroideae (Benn.) de Laub. [as ‘Dammaroides’], and D. sect. Decussocarpus. The name Decussocarpus had been substituted for Nageia Gaertn. as the type of that generic name is based upon mixed elements belonging to Myrtaceae and Podocarpaceae and, in 1969, an Article of the International Code then in force (Art. 70) banned the use of names based on such ‘discordant elements’. This Article was deleted by the Leningrad Congress and the name Nageia once again became legitimate and available for use. This necessitated de Laubenfels's brief paper of 1987, where the three sections of Decussocarpus which he had earlier recognized were respectively renamed Nageia sect. Afrocarpus (J. Buchholz & N. E. Gray) de Laub., N. sect. Nageia and N. sect. Polypodiopsis (C. E. Bertrand) de Laub.

Although Brazil is the centre with the third highest diversity of Cactaceae, the distribution of species at the local scale in Brazil remains largely unknown. This article describes the distribution patterns of the Cactaceae communities in the protected area of the Contendas do Sincorá National Forest (CSNF) in a semiarid region in the north-east of Brazil. Trails were distributed between the altitudes of 290 and 596 m, along which 91 plots (1.8 ha) were established for quantitative surveys. The floristic data were also recorded separately on these trails. With the floristic survey, 18 taxa were recorded, and the quantitative surveys within the plots identified 10 species, represented by 1135 individuals. The distribution patterns of the species of Cactaceae were intermittent, which provided a likely explanation for the differences between the floristic survey and the species composition of the plots. The largest fraction of the floristic variation was not explained by environment or space, and this may be related to climatic alterations in the past, evolutionary processes, natural and anthropic disturbances and other unmeasured environmental variables. The recorded endemic, vulnerable and endangered species of the caatingas of Bahia indicate that broader protection areas for the Cactaceae species in the region of the CSNF are necessary.

Two new Umbelliferae species from S Anatolia are described and illustrated: Chaerophyllum aksekiense A. Duran & Duman and Tordylium ketenoglui Duman & A. Duran.

I. Lenbrassia G.W. Gillett, which has a zygomorphic corolla and four didynamous stamens with anthers joined, is reduced to Fieldia A. Cunn., which has an actinomorphic corolla and four equal stamens with anthers free; the new combination, F. australiana, is made. II. Boea wallichii R.Br. is distinguished from B. hygrometrica (Bunge) R.Br. with which it has been confused. III. Cyrtandra oblongifolia sensu Kraenzlin is described as a new species, C. kalimantana, allied to C. oblongifolia (Blume) C.B.C1. but distinguished by its hairy leaves, fruits, calyx and corolla; the sterile specimens from Borneo quoted under Cyrtandra rufa Bakh.f. are tentatively referred to C. kalimantana. IV. A specimen of Cyrtandra from the Natuna Islands is identified with C. suffruticosa Ridley from Pulau Tioman and the Malay Peninsula; in contrast two other Gesneriaceae from these islands are of Bornean affinity. V. Didymocarpus pteronema is a new species from Tenasserim province of Burma (= Myanmar): it is anomalous in its campanulate corolla and filaments with unilateral membranous wing. VI. Streptocarpus huamboensis is a new species from Angola allied to S. rhodesianus S. Moore.

Asparagus lycaonicus P.H. Davis (Asparagaceae), a species hitherto known only from E Central Turkey, is reported from Iran. A review of Nitraria (Zygophyllaceae) in Iran together with critical comments on the account of the genus in Flora Iranica are given, and Iranian records of N. komarovii Iljin & Lava are referred to Atraphaxis suaedifolia Jaub. & Spach (Polygonaceae).

The genus Acacia Miller is species-rich, and species discrimination is challenging owing to morphological similarities between closely related species. Naming of specimens is particularly difficult in the Middle East, where confusion in taxonomic identification exists within the context of a wider international debate on the generic systematics of Acacia sensu lato. At least five segregate genera for Acacia s.l. have been advocated: Acacia sensu stricto, Vachellia, Senegalia, Acaciella and Mariosousa. Furthermore, identification to species of the only remaining native Acacia s.l. tree in Kuwait is still a matter of controversy. The present study used multilocus chloroplast DNA sequence data analyses following maximum likelihood (ML) and Bayesian approaches to: 1) test the species concepts of Vachellia pachyceras (≡ Acacia pachyceras O.Schwartz) from the Middle East, and Vachellia tortilis (Forssk.) Galasso & Banfi (≡ Acacia tortilis (Forssk.) Hayne) and Vachellia gerrardii (Benth.) P.J.H.Hurter (≡ Acacia gerrardii Benth.) from Kenya, as well as to investigate species divergence times; and 2) identify the only remaining native Acacia s.l. tree in Kuwait (known as the Lonely Tree), as well as other unidentified Acacia s.l. specimens in cultivation. The Bayesian and ML topologies clearly differentiated Vachellia pachyceras, V. tortilis and V. gerrardii, and demonstrated that the three species are distinct. Divergence time estimates using the ML topology suggested that Vachellia gerrardii diverged from a common ancestor no later than the early Pliocene (3.3 Mya), whereas V. pachyceras originated at least 2.0 Mya (Pliocene). The unknown remaining native Acacia s.l. tree in Kuwait and other specimens collected from the nursery were identified as Vachellia pachyceras. These results stress the need to use plastid DNA barcodes complemented by population genetics approaches to address systematic issues in this complex of Acacia s.l. species in the Middle East and the Arabian Peninsula.

Somatic chromosomes at mitotic metaphase of two species and two undescribed populations of Bowenia, and Stangeria eriopus, which were classified in Stangeriaceae, Cycadales, were compared using the standard aceto-orcein staining method. All Bowenia taxa showed a chromosome number of 2n = 18, while S. eriopus showed a chromosome number of 2n = 16. The chromosome number of 2n = 18 in B. ‘Kuranda’ is reported for the first time. The present karyotype analysis indicates that B. ‘Kuranda’ and another undescribed taxon, B. ‘Tinaroo’, are cytotaxonomically closer to B. spectabilis than B. serrulata, and that the karyotype of Stangeria is unlikely to have been derived from that of Bowenia by a simple chromosomal change such as centromeric fission and deletion.

The karyotype of a recently described species of Galtonia (Hyacinthaceae), G. regalis, is described and its cytotaxonomic relationship to other members of the genus examined. Since conflicting cytological patterns for the genus exist in the literature, the chromosome compositions of the three other species, G. candicans, G. princeps and G. viridiflora, are re-investigated. This study demonstrates that the karyotype of Galtonia is uniformly asymmetrical and distinctively trimodal, with 2n=16. Also included in this investigation is the allied monotypic genus Pseudogaltonia. Its karyotype is also asymmetrical, but differs from Galtonia in its chromosome number of 2n=18, and in certain other features.

Chromosome counts for 27 species plus one intersubsectional hybrid are presented from all seven subsections of section Vireya in the genus Rhododendron. Twenty-three are new, and five confirm previously published counts. The plants originate from a wide geographical and altitudinal range; all have a uniform somatic number of 2n=26.

Chromosome numbers for all 23 species of Tilia recognized by the author, and for several subspecies and hybrids, are reviewed. Counts or cytometric analyses for 14 species are reported for the first time; of these, eight species are diploid (2n=82): T. amurensis subsp. taquetii, T. chingiana, T. endochrysea, T. kiusiana, T. mandshurica, T. caroliniana, T. heterophylla and T. mexicana, five are tetraploid (2n=164): T. chinensis, T. henryana, T. miqueliana, T. mongolica and T. paucicostata, and one is octoploid (2n=328): T. nobilis. T. japonica, previously reported as diploid, is tetraploid in Japan (Hokkaidō) and in China. Three new combinations are created: T. amurensis Rupr. subsp. taquetii (C.K. Schneid.) Pigott, T. cordata Mill. subsp. sibirica (Bayer) Pigott and T. platyphyllos Scop. subsp. corinthiaca (Bosc ex K. Koch) Pigott.