No abstract

In this study, pollen grains of Harleyodendron unifoliolatum, Holocalyx balansae, and Uribea tamarindoides, three monospecific genera with Neotropical distribution belonging to the clade Exostyleae, one of the basal lineages of the family Leguminosae, subfamily Papilionoideae, were analyzed. The palynological material was acetolyzed and analyzed under light microscopy (LM) and scanning electron microscopy (SEM). Under LM, small and medium-sized pollen grains were observed, which showed a prolate-spheroidal to prolate shape, 3-colporate, microreticulate and reticulate exine, sexine and nexine of equal thickness in Harleyodendron and Holocalyx, while the sexine was thicker than nexine in Uribea. Analysis under SEM showed finely granulate, psilate, and granulate apertural membrane, while the exine ornamentation varied from perforate-microechinate in Harleyodendron, to perforate in Holocalyx, while in Uribea showed an irregular relief and granular projections on the perforate tectum. The pollen morphology of these species is similar to each other, varying in sexine/nexine ratio, apertural membrane, and exine ornamentation. Harleyodendron has a finely granulate apertural membrane, sexine and nexine of equal thickness, and a perforatemicroreticulate exine ornamentation, Holocalyx shows a psilated apertural membrane, sexine and nexine of equal thickness, and exine ornamentation perforate, and Uribea has a granulate apertural membrane, sexine thicker than nexine, and exine ornamentation with granular projections.

Pollen traits have clarified the classification and understanding of the evolutionary history of different groups of angiosperms, due to their wide morphological diversity. To increase our knowledge on the morphological evolution of the vataireoid clade (Fabaceae, Papilionoideae), a lineage comprising 30 species of Neotropical trees in the genera Luetzelburgia, Sweetia, Vatairea and Vataireopsis, pollen materials of 26 species were acetolysed and analysed using light and scanning electron microscopy. Characters were defined to reconstruct the pollen evolution in each of the ancestral nodes of the phylogenetic tree of the clade using Bayesian stochastic character mapping. All vataireoid genera have relatively variable pollen morphology, ranging from small to medium and subtriangular to circular amb, and their aperture margo may be present or absent. The exine ornamentation varies greatly across the clade: perforate (L. praecox and S. fruticosa); rugulate (L. andradelimae); rugulate-foveolate-perforate (Vatairea guianensis and Vatairea heteroptera); reticulate (Vataireopsis araroba) and microreticulate in most species. Analyses of ancestral character reconstruction revealed multiple events of independent evolution in all pollen traits during the diversification of the vataireoid clade in the last 16 Myr, since the Miocene. Just as evolutionary transitions in floral architecture were so recurrent in the vataireoid clade, pollen evolution was relatively labile and exhibited little phylogenetic conservatism in shape or ornamentation.

Schnella madeleinae, a new species of liana with entire leaves from the Magdalena River Valley of Colombia, is described, illustrated, and aspects related to its distribution, conservation status, and relationships with morphologically similar species are discussed. Schnella madeleinae is characterized by the presence of heteromorphic petals in which the three superior petals are wider (4.5–5.0 × 2.5–3.0 mm) with respect to the two inferiors (5–6 × 2.0–2.5 mm) and oblong laterally compressed legumes of 5.0–6.5 × 1–2 cm. This new species is only known from five localities in the departments of Antioquia and Bolivar. Additionally, a key to the species of the entire leaves of the Schnella sect. Schnella is presented.