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Amazonia is extremely biodiverse, but the mechanisms for the origin of this diversity are still under debate. We propose a diversification model for Amazonia based on the interplay of intrinsic clade functional traits, habitat associations and past geological events, using as a model group the species-rich Neotropical family Marantaceae. Our results show that the species richness of the lineage is predicted by functional strategy, rather than clade age, and thus the fast vs. slow growth functional trade-off is a major determinant of clade diversification in Marantaceae. Rapidly growing clades were mostly associated with highly productive habitats, and their origin and diversification dynamics matched the expansion of fertile soils mediated by Andean uplift c. 23 Mya. Fast-growth strategies probably led to fast molecular evolution, speeding up speciation rates and species accumulation, resulting in higher numbers of extant species. Our results indicate that pure allopatric-dispersal models disconnected from past geological and ecological forces may be inadequate for explaining the evolutionary and diversity patterns in Amazonian lowlands. We suggest that a coupling of the functional trait-niche framework with diversification dynamics provides insights into the evolutionary history of tropical forests and helps elucidate the mechanisms underlying the origin and evolution of its spectacular biodiversity.

Nodes are interfaces between stems and leaves. Vascular bundles originate here and elongate into leaves and internodes. In Marantaceae, internodal bundles are highly diverse, including inverted bundles in the climbing genus Haumania. The objective of this paper is to characterize bundle forms, their position across the stem and their connection to leaves and short shoots in Haumania spp. and other unrelated African branch-angle climbers in the family (Hypselodelphys, Trachyphrynium). We question whether bundle inversion is a genus-specific trait in Haumania or related to the climbing growth form. Vascular bundles in internodes are scattered across the stem diameter in a characteristic pattern. Four (to five) bundle types follow each other in a centripetal order from highly sclerenchymatic ‘a’-bundles close to the epidermis to ‘d’-bundles in the centre with a low sclerenchyma proportion. Inverted bundles only appear in internodes of Haumania, making this trait a synapomorphy for the genus. The nodes show stem, leaf and short shoot bundles in a remarkably diverse pattern with partitioned phloem clusters and apparently augmented xylem elements. Our preliminary conclusion is that the inversion of bundles happens when leaf and short shoot traces join the main axis bundle layers.

Recognition and delimitation of taxonomic categories of biological organisms are still challenging and full of controversy. We used Ischnosiphon as a model to unravel the importance of morphometrics as individual-based variables to disentangle the morphological variability of plant species. Ischnosiphon spp. continue to be problematic for users, taxonomists and ecologists, due mainly to the huge morphological variability, the species criteria and circumscription proposed for many taxa and the many habitat and vegetative macro-morphological characters lacking in most currently available exsiccates. Twenty-three morphometric variables were sampled from 228 individuals, belonging to 22 Ischnosiphon spp. Principal components and discriminant multivariate analyses were used to describe and identify patterns of morphological variation in Ischnosiphon. Individual-landmark assessment analysed with multivariate methods captured morphometric intraspecific diversity and morphological variability in Ischnosiphon spp., along with the continuous variation of important morphological traits. By examining the morphology of Ischnosiphon spp. through individual-landmark assessment, we demonstrate that different morphological species concepts used today in the identification of the species are difficult to apply. We propose a replicable and analytical framework to accommodate individual variability in species diagnosis in morphologically diverse plant groups.

Marantaceae consist of species with asymmetric leaves of two types: those with either a wider left or right half; this asymmetry is related, respectively, to clockwise or counterclockwise convolute vernation. In this study, we analysed whether anatomical differences in the leaf edges, i.e. the anatomical asymmetry, were related to the orientation of the convolute vernation and to the asymmetry of leaf morphology, and whether these differences supported the organization of the clades in the family. Transverse sections of the mid third of the leaf buds expanded to the height of the right and left edges of the blades were prepared for 19 species belonging to 11 genera, using cyto-histological techniques. Anatomical analyses of the blade edges revealed that there is a relationship between morphological asymmetry and anatomical asymmetry that has never before been ascribed to the family. The anatomical data support differences between the arrangements in two of the three Neotropical informal groups. In the Calathea clade, Calathea showed much more similarity with Goeppertia than with Ischnosiphon and Monotagma, since they are the only genera that do not present with anatomical asymmetry. In the Maranta clade, Ctenanthe, Saranthe and Stromanthe appear to be related to one another, as they share strong anatomical asymmetry and fibrous edges. These characteristics, however, are not observed in Myrosma, which in turn is more anatomically similar to Maranta.

The flowers of Marantaceae (∼ 550 species) exhibit a highly derived pollination mechanism within Zingiberales, with a rapid and irreversible style movement based on a close synorganization of different floral parts. Given the complexity of the structure, we assume that little variation is possible if functionality is to be maintained. To test this, we investigated how much floral diversity exists in the clade and whether this diversity potentially influences the breeding system and placement of pollen on the pollinator. Flowers of 66 species covering the five major phylogenetic clades of the family were analysed. All species are similar in their basic flower construction: the fleshy staminode forms the tunnel-shaped roof of the flower and narrows the tube with stiff swellings, and the hooded staminode holds the style under tension and narrows the flower entrance with its trigger appendage. Despite morphological diversity of the pollination apparatus, functionality is maintained by coordinated variation of the fleshy and hooded staminodes. Autogamy is usually avoided by herkogamy. However, in a few exceptions, subtle morphological changes alter the breeding system from allogamy to autogamy. Variable floral proportions allow for differential pollen deposition potentially causing mechanical isolation between sister taxa. This study clearly illustrates that structural variation is not only present in the highly synorganized flowers of Marantaceae, but that it also creates potentially new options for evolutionary diversification. © 2012 The Linnean Society of London, Botanical Journal of the Linnean Society, 2012, 168, 300–322.

Maranta is a neotropical genus, species of which are found in moist and shaded habitats in forests and in the cerrado. During the preparation of Maranta’s monograph for the Flora Neotropica, four new species were discovered and are now described: Maranta longiflora S.Vieira & V.C.Souza, Maranta coriacea S.Vieira & V.C.Souza, Maranta pulchra S.Vieira & V.C.Souza and Maranta purpurea S.Vieira & V.C.Souza. These species are found in dry habitats, frequently near watercourses or occasionally in humid and shaded places. Two, M. pulchra and M. purpurea, seem to be endemic to the state of Mato Grosso. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society, 2008, 158, 131–139.

Relationships of Marantaceae were estimated from nucleotide sequence variation in the rps 16 intron (plastid DNA) and from morphological characters. Fifty-nine species (21 genera) formed the ingroup, and 12 species (12 genera) of other Zingiberales formed the outgroup. There is no support for the traditional subdivision of Marantaceae into a triovulate and a uniovulate tribe or the informal groups previously proposed. The so-called Donax group forms a paraphyletic grade that is basal within Marantaceae. Thalia appears as the distal branch of this grade, but its position is not supported in jackknife analysis. The so-called Calathea group is monophyletic in all shortest trees but not supported with greater than 50% jackknife. The genus Calathea appears to be paraphyletic. The Maranta andPhrynium groups are clearly polyphyletic. Maranta, Koernickanthe, and genera of the Myrosma group, all neotropical, form a strongly supported monophyletic group. The sister of this group is the palaeotropical genusHalopegia . Koernickanthe is nested within Maranta, as this genus is traditionally circumscribed. The African genera Ataenidia and Marantochloa form a strongly supported clade in which Ataenidia is the sister group to Marantochloa. Based on phylogeny it is concluded that Africa, in spite of being much poorer in species, is the most likely ancestral area of Marantaceae.