Julián Molero

A worldwide molecular phylogeny and classification of the leafy spurges, Euphorbia subgenus Esula (Euphorbiaceae)

The leafy spurges, Euphorbia subg. Esula, make up one of four main lineages in Euphorbia. The subgenus comprises about 480 species, most of which are annual or perennial herbs, but with a small number of dendroid shrubs and nearly leafless, pencil-stemmed succulents as well. The subgenus constitutes the primary northern temperate radiation in Euphorbia. While the subgenus is most diverse from central Asia to the Mediterranean region, members of the group also occur in Africa, in the Indo-Pacific region, and in the New World. We have assembled the largest worldwide sampling of the group to date (273 spp.), representing most of the taxonomic and geographic breadth of the subgenus. We performed phylogenetic analyses of sequence data from the nuclear ribosomal ITS and plastid ndhF regions. Our individual and combined analyses produced well-resolved phylogenies that confirm many of the previously recognized clades and also establish a number of novel groupings and place- ments of previously enigmatic species. Euphorbia subg. Esula has a clear Eurasian center of diversity, and we provide evidence for four independent arrivals to the New World and three separate colonizations of tropical and southern Africa. One of the latter groups further extends to Madagascar and New Zealand, and to more isolated islands such as Reunion and Samoa. Our results confirm that the dendroid shrub and stem-succulent growth forms are derived conditions in E. subg. Esula. Stem- succulents arose twice in the subgenus and dendroid shrubs three times. Based on the molecular phylogeny, we propose a new classification for E. subg. Esula that recognizes 21 sections (four of them newly described and two elevated from subsectional rank), and we place over 95% of the accepted species in the subgenus into this new classification.

Karyological evolution and molecular phylogeny in Macaronesian dendroid spurges (Euphorbia subsect. Pachycladae)

Abstract. Euphorbia subsect. Pachycladae is a taxon of primarily Macaronesian distribution, defined by morphological and biogeographical criteria. On the basis of morphological data, it is a heterogeneous group within which at least three complexes of species can be distinguished. To ascertain whether it is a natural group and discover its phylogenetic relations, we performed a cladistic analysis of the sequences of ribosomal nuclear DNA and a karyological study. The results of the two studies are concordant and show that the sub-section is polyphyletic and includes three different groups. The first monophyletic group is made up of the Macaronesian endemics E. atropurpurea complex and E. lamarckii complex, which form a polytomy with E. dendroides as the basal species. The lauroid species E. longifolia and E. stygiana represent the second monophyletic group, which derive from Mediterranean forms of E. sect. Helioscopia Dumort. Both species are paleopolyploid (2n=44) with highly symmetrical karyotypes. Finally, E. balsamifera, with a Canarian, African and Arabian distribution, remains isolated in a basal position. Its karyotype, with 2n=20 chromosomes, differs from the Macaronesian model and displays analogies with African cactiform spurges. On the basis of the results, some hypotheses are formulated about speciation processes in the three groups.

Origin and evolution of the South American endemic Artemisia species (Asteraceae): evidence from molecular phylogeny, ribosomal DNA and genome size data.

Genus Artemisia is thought to have reached the Americas across the Bering Strait from Asia during the late Tertiary, but the systematic position of the South American endemic species and the migration routes towards the south have not yet been studied. We used nuclear DNA sequences to unravel the interspecific relationships among the South American Artemisia and their connections with the remaining species of the genus, as well as using fluorescent in situ hybridisation and genome size assessments to characterise this polyploid complex. Most of the species are clustered in a monophyletic clade, nested within the American endemic clade, with the exception of A. magellanica Sch. Bip., which appears segregated from the other American species and constitutes a clade together with A. biennis Willd. Fluorescent in situ hybridisation and genome size data revealed that monoploid genome size remains quite constant across ploidy levels and a proportional increase of ribosomal loci was detected, a dynamic not usually found in this genus. The results are discussed in the light of evolutionary processes which occur in plants, and plausible origins for the South American endemic species are hypothesised.

Las cubetas arreicas al sur de Bujaraloz (Valle del Ebro). Contribución a su estudio fitocenológico

Se preenta un estudio de la vegetacion y condiciones mabientales de algunas de las lagunas saladas situadas en la comarca de Los Monegros. Se reconocen 13 asociaciones y 11 subasociaciones. Por ultimo, se sugieren algunas medidas para la conservacion de estos enclaves.

Conservation assessment of Aquilegia paui (Ranunculaceae): a case study of an extremely narrow endemic.

The extremely rare Aquilegia paui (Ranunculaceae) was described in 1920 but was not found again until 1999, when it was discovered in the Parc Natural dels Ports in Tarragona Province, Spain. This species had been confused with the widespread A. vulgaris and consequently its taxonomic and conservation status had been misinterpreted. Based on the limited range of A. paui and the level of disturbance of its habitat we recommend that it is categorized as Endangered on the IUCN Red List. We summarize the conservation actions available for such extremely narrow endemic plant species and make appropriate recommendations for the conservation of A. paui .

Molecular Phylogeny of the Genus Ptilostemon (Compositae: Cardueae) and Its Relationships with Cynara and Lamyropsis

Abstract Ptilostemon is a fine example of the representatives of the eastern groups of the Cardueae that have diversified in the western Mediterranean. Relationships to Cynara, which exhibits a similar distribution, and Lamyropsis, which is morphologically closer according to previous studies, are investigated using Bayesian analysis of DNA sequences of the plastid intergenic spacer ycf3-trnS and two nuclear regions, the ETS and ITS spacers. The sectional classification and biogeography of Ptilostemon are also revised in the light of the molecular phylogeny Our results suggest that Cynara is the most plausible sister genus to Ptilostemon. Some paralogous copies of the ETS region found among species of the three genera by cloning are interpreted as incomplete lineage sorting of ancestral polymorphisms. The current sectional classification of Ptilostemon shows excessive fragmentation, which does not agree with our phylogeny, and therefore a more synthetic classification is proposed. The present distribution of Ptilostemon indicates that there were two colonization events in the western Mediterranean region, paralleling a similar pattern of successive waves already suggested for Cynara.

Structure of the apertural sporoderm of pollen grains inEuphorbia andChamaesyce (Euphorbiaceae)

The tricolporate pollen grains of 38 Mediterranean and Macaronesian species ofEuphorbia L. andChamaesyceS. F. Gray have a special apertural sporoderm not found in the other taxa of theEuphorbiaceae. At the apertural margo the ectexine is thinner because of shorter columellae and the thin, fragmented or even absent foot-layer. Ectexinous granules, mixed with endexinous material, are present near the ora. The endexine is homogeneous and thickened under the colpi (at the end and at the proximity of the end of colpus). Around the ora, the endexine is granulate and lamellar with irregular cavities. The apertural intine presents a characteristic structure with thickenings running along both sides of the colpi. The arrangement and structure of these intinous thickenings depend on the distance from the ora. This special morphology of the intine is present in all taxa studied here. The genusEuphorbia is considered to be the most evolved taxon of this family. The characteristic apertural sporoderm may be an adaptative modification to different physiological conditions, so it may present an apertural mechanism which is more adapted to harmomegathic changes and thus facilitate the germination and the formation of the pollen tube.