A long-flowering Hechtia (Bromeliaceae): Hechtia sanchezii, a new species from San Luis Potosí, Mexico

Background: Hechtia is known among Bromeliaceae by its unisexual, sexually dimorphic, mainly fragrant flowers and dioecy; delimitation of taxa particularly on those with lateral inflorescence, requires qualitative morphological evidence from both sexes, because dimensions of structures change during its growth. Hypotheses: Hechtia species are delimitated based on a combination of discrete morphological characters from both sexes, associated with narrow geographical distributions. If examination of populations of San Luis Potosí shows characters that place the taxon in the genus and distinguish it from other species in Hechtia, the taxon will be described as new. Taxon: Hechtioideae, Hechtia sp. nov. Study site and dates: Mexican State of San Luis Potosí and vicinities, 2015-2021. Methods: Live plants as well as herbarium material of the new taxon and the most morphological similar species, were analyzed, with examination of inflorescences and flowers of both sexes, fruits, and seeds. Geographical distribution was mapped and conservation status using IUCN criteria is reported for the new species. Results: Hechtia sanchezii has been confused with H. glomerata since both share lateral, glomerulate-like infructescences, but H. sanchezii shows red to ferruginous indumenta on floral bracts and sepals (vs. white), these red (vs. greenish or brownish), pink petals (vs. white), scentless (vs. fragrant) flowers, stamens with filaments of two lengths, three epipetalous, and three alternating with petals (vs. two lengths but all filaments epipetalous). Conclusions: Morphological and geographical evidence allow the recognition of H. sanchezii as a new species native from San Luis Potosí, Mexico.