ABSTRACT Floral nectaries are linked with animal pollinators and floral specialization, characterizing some plant groups, such as the mostly Neotropical Vochysiaceae. The phylogeny of these plants has been revised based on molecular data, but their conspicuous spurs were mostly neglected. The appendicular or receptacular origin of these spurs has been discussed but without ontogenetic or anatomical study, and the association between spur structure and pollination systems was never assessed. We studied the spurs of species of four genera of Cerrado Vochysiaceae (tribe Vochysieae), documenting their vascularization and comparing their structure to previously described pollination systems. The spur structure was roughly similar among species, and vascularization confirmed their appendicular origin. Subepidermic secretory tissue surrounded the lumen of the spur and nectar was secreted through nectarostomata. Besides differences in size and cuticle striation, no other association between spur structure and pollination system was observed. However, the structure is somewhat distinct in Qualea parviflora, which sports a pluriseriate internal epidermis padding the spur lumen, which may provide protection against damage by the large bees that visit these relatively small flowers. The conservative histology and vasculature somewhat confirmed the monophyly of the tribe Vochysieae and the appendicular origin of the spur in the Cerrado Vochysiaceae.

Ageratum has a complex circumscription, and recent studies have indicated its polyphyletism. The genus has been placed in the tribe Eupatorieae whose embryology is not fully known. Embryological data are conservative and important indicators of phylogenetic relationships and can improve family relationships. This study presents, for the first time in Eupatorieae, embryological data for Ageratum conyzoides and A. fastigiatum. Both species have common features of the family such as a unitegmic anatropous ovule, basal placentation, secretory tapetum, Polygonum megagametophyte, and Asterad embryogenesis. The data obtained reinforce the heterogeneity of the family embryology and show, for the first time, the anther wall development of the monocotyledonous type for Asteraceae. The species studied show also differences between themselves. A. conyzoides has bisporangiated and introrse anthers, conspicuous pappus, and cypselae with trichomes on the ribs, whereas A. fastigiatum has tetrasporangiate and latrorse anthers, pappus absent at maturity, and glabrous cypselae. The data presented support recent phylogenetic molecular studies, suggesting the replacement of A. fastigiatum to another genus along with Gyptidinae.

The ability of plants to generate fertile offspring is influenced by morpho-physiological and ecological factors. Hence, reproductive success is directly linked to factors affecting quantity and quality of their progeny. In the Cerrado (savanna) of Brazil, the Vochysiaceae is a widely distributed and ecologically important family. Factors affecting pre-dispersal seed predation and abortion were studied for populations of Callisthene fasciculata, C. major, Qualea multiflora and Q. parviflora. To characterize differences between genera, as well as among species, study areas, and individuals, we quantified pre-dispersal seed predation and abortion. Differences of seed abortion among the species were related to intrinsic reproductive features and not to area or other factors. In contrast, seed predation varied not only among species but also among areas and among individuals. Only C. fasciculata showed no seed predation. In Qualea species, insect predators were found inside the seeds; whereas predators of Callisthene species were outside seeds. In both genera, seed abortion correlated negatively with area size, as did pre-dispersal seed predation, which suggest seed abortion may be a counter-measure to avoid predation. Although seed abortion and predation reduced the progenies of the studied species, seed production did not differ from other Cerrado species.

Espécies de Vochysiaceae são árvores e arbustos, principalmente do neotrópico, e constituem elementos característicos dos cerrados do Brasil Central. A família foi subdividida nas tribos Erismeae, com três gêneros e Vochysieae, com cinco gêneros. A superfície estigmática de seis espécies de Vochysiaceae foi caracterizada, representando quatro gêneros de Vochysieae (Vochysia, Salvertia, Callisthene e Qualea). Foram coletados botões em diferentes fases de desenvolvimento e flores abertas. Características gerais foram observadas no material fresco e a receptividade estigmática foi definida pela ação esterásica. Pistilos, fixados e incluídos em "paraplast", foram secionados e corados para análises histológicas. Estigmas de flores abertas foram observados em microscopia eletrônica de varredura. Os estigmas de todas as espécies eram úmidos e apresentavam ação esterásica em pré-antese e na antese. Apresentavam, ainda, continuidade com o tecido transmissor de natureza secretora. Em Vochysia e Salvertia, a superfície estigmática era formada por tricomas multicelulares uniseriados, enquanto nas espécies dos demais gêneros, a superfície era formada por papilas unicelulares. A secreção que recobre os estigmas de todas as espécies fluía sem que houvesse ruptura da superfície estigmática e os tubos polínicos cresceram entre as papilas ou tricomas. As diferenças na superfície estigmática observadas corroboram a reconstrução filogenética separando dois clados e indicando que a tribo Vochysieae não é monofilética. Entretanto, não foi possível associar as características estigmáticas com os sistemas de polinização presentes na família.

The Vochysiaceae are Neotropical trees and shrubs, common in the savanna areas in Central Brazil (Cerrados). The family has been traditionally divided into two tribes: Erismeae, with three genera, and Vochysieae, with five genera. We investigated the stigmatic surface of six Vochysiaceae species, belonging to four genera of Vochysieae: Vochysia, Salvertia, Callisthene and Qualea. Flowers and buds at different developmental stages were collected. Morphological features were observed on fresh material and stigmatic receptivity was inferred based on esterasic activity. Pistils were fixed and embedded in paraplast and sectioned on a rotary microtome; the sections were stained before histological analysis. Stigmas of open flowers were also observed by scanning electron microscopy. Stigmas of all species were wet and showed esterasic activity at pre-anthesis and anthesis stages. Stigmatic surface was continuous with transmitting tissue of glandular nature. Vochysia and Salvertia stigmatic surfaces were formed by multicelular uniseriate hairs, and species of the remaining genera showed papillate surface. The exudate over mature stigmas in all species flowed without rupture of stigmatic surface and pollen tubes grew down between hairs or papillae. Differences on the stigmatic surface agreed with a phylogenetic reconstruction that separated two clades and indicated that Vochysieae is not monophyletic. Stigmatic features could not be associated with pollination and breeding systems.