Flower and fruit characters in the early-divergent lamiid family Metteniusaceae, with particular reference to the evolution of pseudomonomery

Evaluating the morphological relationships of angiosperm families that still remain unplaced in the current systems of classification is challenging because it requires comparative data across a broad phylogenetic range. The small neotropical family Metteniusaceae was recently placed within the lamiids, as sister to either the enigmatic Oncothecaceae or the clade (Boraginaceae + Gentianales + Lamiales + Solanales + Vahliaceae). We examined the development of two of the primary diagnostic traits of Metteniusaceae, the moniliform anthers and the unilocular gynoecium. The gynoecium is 5-carpellate, and contains two ovules with a massive, vascularized integument. Late sympetaly and unitegmic ovules support placement of Metteniusaceae in the lamiids. The 5-carpellate gynoecium is consistent with a sister-group relationship between Metteniusaceae and Oncothecaceae. The gynoecium of Metteniusaceae is unusual in that it is monosymmetric throughout ontogeny, which indicates pseudomonomery; the five carpel initials are congenitally fused by their margins and form a single locule; the two ovules develop from the two smallest and most poorly developed lateral carpels. Comparisons with other pseudomonomerous taxa allow us to propose division of the complex processes leading to pseudomonomery into eight characters, including carpel number and fusion, gynoecial symmetry, timing of carpel reduction, and number and position of nonfertile carpels.     

Leaf Development, Metamorphic Heteroblasty and Heterophylly in Berberis s. l. (Berberidaceae)

Shoot development of temperate and tropical members of Berberis s. l. was examined in order to assess: (1) the homology of the spines along the long shoots and the foliage leaves that form on the short shoots; (2) the occurrence of heterophylly and/or heteroblasty in the genus; and (3) the structural correspondence between cataphylls, spines, and foliage leaves. The 1-5-armed spines have been interpreted as modified compound leaves lacking stipules, as a modified lamina (central spine) with stipules (lateral spines), or less often, as transformed branches, or as epidermal outgrowths. On the other hand, the foliage leaves of the short shoots have been interpreted as leaflets of palmately compound leaves. Our results indicate that there are three distinct leaf types per node: (1) Leaves modified in spines spirally arranged in long shoots; (2) foliage, expanded leaves densely arranged in short shoots; and (3) cataphylls protecting axillary buds. The spines are leaf homologs with a clear distinction between the leaf base with stipules, and a laminar portion modified into the 1-5-armed spine; the lateral spines are not stipules as they arise from the marginal meristem of the laminar portion, and not from the leaf base. The foliage leaves also have stipules flanking the leaf base. Both spiny leaves and foliage leaves develop an articulation between the base and the laminar portion. Cataphylls of the short shoots of Berberis s. str. and those of the reproductive short shoots of Mahonia correspond to the entire leaf base, but those of the renewal (vegetative) shoots of Mahonia are spiny and have an odd vestigial pinnately compound lamina. Heterochrony due to ontogenetic truncation caused by the formation of the terminal inflorescence at the apex of the short shoots could be responsible for the lack of petiole/lamina differentiation in the foliage leaves. The spiny long-shoot/foliose short-shoot system of branching in Berberis s. str. appears to be genetically and phylogenetically fixed and not environment-dependent. This represents a clear example of metamorphic heteroblasty sensu Zotz et al. (Botanical Review 77:109–151, 2011) with further occurrence of heterophylly along the short shoots.     

Aristolochia zebrina sp. nov. (Aristolochiaceae) from southeastern Brazil

Aristolochia zebrina is described, illustrated and discussed in comparison with the two most similar species, A. papillaris Mast. and A. tamnifolia (Klotzsch) Duch. The new species is distinguished from its relatives mainly by the ellipsoid utricle, the narrowly ovate, revolute, and efimbriate floral limb with dark purple longitudinal stripes inside, and the glabrous and smooth capsules, which are broadly cylindrical. So far, the new species has only been found in ‘restingas’ (sandy soils) and wet tropical Tabuleiro forests in northern Espírito Santo, southeastern Brazil.     

Floral resources foraged by Geotrigona argentina (Apidae,Meliponini) in the Argentine Dry Chaco forest

This study is the first contribution to knowledge of the relationships between Geotrigona argentina and the plants of the Argentine Dry Chaco forest. A total of 1260 g of honey (corresponding to 146 pots) and 763 g of pollen (63 pots) stored in four underground nests was studied. The honey pots from each nest were homogenised and the four honey samples were analysed by melissopalynological methods, whereas the pollen pots were studied individually. Both classical counts and counts affected by the volume of the pollen types were carried out. Pollen data were statistically analysed. Additional data on both protein and lipid content is also provided. A total of 39 pollen taxa were identified. Pollen collection was focused on a few pollen taxa: Prosopis, Castela coccinea, Maytenus and Capparis; these taxa, together with Ziziphus mistol and Pisonia zapallo, were also important nectar sources. The preliminary results show that pollen collection varied seasonally, being most diverse in the summer when G. argentina incorporates herbaceous plants into its diet. The pollen collection spectrum of G. argentina is similar to that of other Trigonina bees in that the main plant species collected are a few large shrubs or trees, whose flowering consists of small and clustered flowers. Pots with large amounts of monofloral loads with pollen from only a few species suggests an organised foraging behaviour that includes the recruitment of foragers, such as that observed in other eusocial bees.     

On the supposed polycotyledony and lack of endosperm in <Emphasis Type="Italic">Psittacanthus</Emphasis> (Loranthaceae)

Psittacanthus is one of the few genera of Loranthaceae that has been described as lacking endosperm and developing polycotyledonous embryos. Based on the study of seeds and seedlings of 12 species of Psittacanthus, we demonstrate that the embryo has two leafy cotyledons surrounded by a massive, compound, starchy, chlorophyllous endosperm, as in most species of Loranthaceae studied so far. We show that what has been described as a polycotyledonous embryo actually corresponds to the endosperm, and that, along with the fruit remains, it can reattach to the host after the seedling itself has anchored. The morphological, developmental and taxonomical implications of these findings are discussed.     

Multiphoton fluorescence microscopy with GRIN objective aberration correction by low order adaptive optics

Graded Index (GRIN) rod microlenses are increasingly employed in the assembly of optical probes for microendoscopy applications. Confocal, two-photon and optical coherence tomography (OCT) based on GRIN optical probes permit in-vivo imaging with penetration depths into tissue up to the centimeter range. However, insertion of the probe can be complicated by the need of several alignment and focusing mechanisms along the optical path. Furthermore, resolution values are generally not limited by diffraction, but rather by optical aberrations within the endoscope probe and feeding optics. Here we describe a multiphoton confocal fluorescence imaging system equipped with a compact objective that incorporates a GRIN probe and requires no adjustment mechanisms. We minimized the effects of aberrations with optical compensation provided by a low-order electrostatic membrane mirror (EMM) inserted in the optical path of the confocal architecture, resulting in greatly enhanced image quality.