Mistletoe establishment relies heavily on a seed reaching a proper host plant. Small frugivorous birds usually disperse large numbers of mistletoe seeds. However, in the field, mistletoes are absent from some potential available hosts. We investigated whether the mistletoe Phoradendron crassifolium has some preferences for specific host trees in a fragment of Atlantic Forest in southeast Brazil. We surveyed 397 tree individuals of 50 species within 25 families. Seven of those species (14%) bore P. crassifolium infections. Although prevalence at the individual level was low (11.6%), there were marked deviations in infection levels among species and families. Most (87%) of the infections (40 of 46) occurred in species belonging to the families Anacardiaceae (Lithraea molleoides and Tapirira guianensis) and Siparunaceae (Siparuna guianensis), which nevertheless accounted for only 26% of the potential individual hosts (103 of 397). We also performed an experiment simulating bird behavior. We inoculated 480 mistletoe seeds to the bark of four potential hosts in field, following the fate of the seeds for five months. No differences in host preference were observed. The low specificity detected at the local level was confirmed by a survey of exsiccata collected over the geographical distribution of the mistletoe, suggesting that P. crassifolium prevalence is more dependent on dispersal limitation than on mistletoe-host compatibility.

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In this study, we developed and characterized microsatellite for Aspidosperma pyrifolium Mart. & Zucc., considered a species complex due to its morphological variation and disjunct distribution. This complex is predominant in the "Caatinga" of Northeast Brazil, but also occurs in semi-deciduous seasonal forests of central Brazil, in Chaco areas of the southwestern Brazil, Bolivia and Paraguay. These vegetations are included in the concept of Seasonally Dry Tropical Forests (SDTFs). SDTFs are considered one of the most endangered forests in the world due to intense anthropic pressure and high endemism. Concerning endemic species of SDTFs, little is known about the genetic structure of A. pyrifolium and the effects of disjunct distribution on their gene flow and genetic diversity. In this study, 16 polymorphic and four monomorphic microsatellites were characterized in 82 Aspidosperma pyrifolium individuals from three populations in Brazil's Northeast. The transferability resulted in an average of seven markers, amplified in 11 other species of the genus (A. brasiliense A.

Background and aims – The Atlantic Forest is among the five most important biodiversity hotspots in the world, harbouring one of the highest levels of endemism and species richness in the tropics. The region has been suggested as a centre of diversity for the genus Hippeastrum, which comprises about one hundred species distributed throughout the Neotropics. Due to its large and showy flowers, the genus is highly sought after by collectors and horticulturists around the world, with hundreds of hybrids produced and traded for centuries. However, most of its species are still known from only one or a few populations, and several are officially recognized as endangered. Monographic studies on the genus Hippeastrum in Brazil have revealed two likely microendemic new species from the Atlantic Forest. Material and methods – The morphological descriptions of the new species are based on herbarium specimens and cultivated plants, as well as in situ observations. Descriptions and measures were taken following standard procedures. Preliminary conservation assessments followed IUCN guidelines and criteria. Key results – Both species show typical morphology of the subgenus Hippeastrum, in which they should be placed. They can be distinguished from similar taxa, including some of the most widely distributed and known species of the genus, by several floral characters. Data on ecology, conservation, and photographs and illustrations are provided, as well as comparisons with related species. An identification key to the Brazilian Atlantic Forest species of Hippeastrum is provided, accompanied by photographs of these species in their natural habitats. Conclusion – The new species are considered critically endangered due to their single known location and small population size. The findings reinforce the need for continued sampling across different regions of the Atlantic Forest, as well as the importance of systematic studies conducted by specialist taxonomists.