To print in red ink: two new species of Hippeastrum (Amaryllidaceae) from the Brazilian Atlantic Forest

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.