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Apomixis and adventitious polyembryony have been reported for several species of Bombacoideae, including Eriotheca pubescens, a tree species of the Neotropical savanna (Cerrado) areas in Brazil. However, the origin of polyembryonic seeds and their importance for the reproduction of the species remained to be shown. Here, we analyzed the early embryology of(More)
BACKGROUND AND AIMS The genus Cytinus is composed of rootless, stemless and leafless parasites whose flowers are only visible during the reproductive period when they arise from the host tissues. Most of the taxa occur in Madagascar and South Africa, where mammal pollination has been suggested for one species. There is only one species in the Mediterranean(More)
The occurrence of cyathia containing staminate flowers but lacking a pistillate flower was studied in 17 species of Euphorbia. Male cyathia were found in the majority of species studied (88.2%) giving functional andromonoecy. In the male cyathia, the pistillate flower is generally totally absent, but sometimes a vestigial pistillate flower with a(More)
Floral symmetry and fusion of perianth parts are factors that contribute to fine-tune the match between flowers and their animal pollination vectors. In the present study, we investigated whether the possession of a sympetalous (fused) corolla and bilateral symmetry of flowers translate into decreased intra-specific variability as a result of natural(More)
Determining the sources of floral variation is crucial to the understanding of floral evolution. Architectural effects and phenotypic plasticity in development can play an important role in intraplant floral variation, giving rise to gender dimorphism or sexual specialization. Amphicarpic plants have another source of floral variation that could also be(More)
UNLABELLED • PREMISE OF THE STUDY Whole genome duplication (WGD) and specific polyploidy events marked turning points for angiosperm genome structure and evolution. Therefore, cytogenetic studies of polyploidy-prone groups such as the tropical Malvaceae and plant formations such as as the Brazilian Cerrado have gained further importance. We present new(More)
BACKGROUND AND AIMS In andromonoecious taxa with separate floral types along the inflorescence, architectural or plastic effects can simulate floral sexual dimorphism. Both the primary and secondary sexual characteristics of the cyathia of the protogynous andromonoecious species Euphorbia nicaeensis were analysed according to their sex and arrangement on(More)
Mycorrhizae are widespread mutualistic symbioses crucial for the functioning of terrestrial ecosystems. Not all plants associate with mycorrhizae; most parasitic plants have been suggested to be nonmycorrhizal because they have developed alternative strategies to obtain nutrients. In endophytic parasitic plants, whose vegetative bodies grow completely(More)
In a recent study (American Journal of Botany 97: 730-737), we described the first case of a tripartite association in natural conditions among a holoparasitic plant (Cytinus), its host Cistaceae species, and mycorrhizal fungi at an anatomical level. In a letter to the editor, Brundrett (American Journal of Botany 98: 595-596) commented on our manuscript(More)
The hypothesis that reproductive cost differs between sexes was tested in Juniperus communis subsp. alpina along an altitudinal gradient. Sex ratio (male : female) increased significantly with elevation, and above 2,600 m it was significantly male-biased. The reproductive effort was markedly greater for females than for males at all elevations. However,(More)