A new species of Pitcairnia (Bromeliaceae) with nocturnal anthesis from Oaxaca, Mexico

Background: Pitcairnia is the third largest bromeliad genus in Mexico with 57 species and ca. 82.5 % endemism, and is characterized mostly by zygomorphic, ornithophilous flowers of diurnal anthesis in several hues of red, orange, or yellow, whereas white or green flowers are uncommon. Moreover, there are just a few species with nocturnal anthesis in Megamexico. One of them is documented and discussed here. Questions: Is the Pitcairnia with campanulate, fragrant flowers of nocturnal anthesis from Oaxaca different from other species with similar characters native to Mexico and the Neotropics and what is its conservation status? Studied species: Pitcairnia abundans, P. lokischmidtiae, P. zapoteca. Study site and dates: Oaxaca, Mexico, 2016-2024. Methods: Live plants, herbarium material, protologues, and high-resolution images of herbarium specimens, both of the new taxon and of morphologically similar taxa, were studied and compared against each other. The conservation status of the new species was assessed using the IUCN criteria. Results: Pitcairnia zapoteca is similar but different at the species level from P. lokischmidtiae from Jalisco; both share campanulate flowers of nocturnal anthesis and a musky or frutal fragances. The conservation status of the new taxon is assessed as DD. Conclusions: Pitcairnia zapoteca is a new species, only known from the type locality in the state of Oaxaca and only one of three Mexican species with campanulate, white, yellowish or greenish flowers of nocturnal anthesis. The assessment the true conservation status of the new taxon requires detailed exploration of the SE portion of Oaxaca. Antecedentes: Pitcairnia es el tercer género más rico en especies de Bromeliaceae en México con 57 especies y ca. 82.5 % de endemismo; está caracterizado por sus flores mayormente zigomorfas y ornitófilas de antesis diurna. Especies de antesis nocturna son muy pocas en Megamexico, incluyendo una colectada recientemente en la zona oriental de Oaxaca. Preguntas: ¿Es la Pitcairnia de Oaxaca con flores campanuladas de antesis nocturna diferente a otras especies con caracteres similares nativas de México y del neotrópico? ¿Cuál es su estado de conservación? Especies de estudio: Pitcairnia abundans, P. lokischmidtiae, P. zapoteca. Sitio y años de estudio: México, Oaxaca, 2016-2024. Métodos: Plantas vivas, material de herbario, protólogos e imágenes de alta resolución de ejemplares de herbario, tanto del nuevo taxón como de taxones morfológicamente