Morphological and Molecular Diagnostic Characters Reveal a New Species of Pachyphytum (Crassulaceae)

Abstract: Pachyphytum viscidum (Crassulaceae: Saxifragales) is described as a new species to science. The specimens analyzed come from the Sierra de Santa Bárbara, Guanajuato, Mexico. Some morphological diagnostic characters for the new species are: sticky stems and leaves; dark green leaves; absence of wax on all their organs; and pale pink flowers. The new species is placed in the section Diotostemon of the genus, with possible proximity to P. brevifolium and P. hookeri. DNA sequence analysis from the matK and rbcL chloroplast regions, as well as ITS2 nuclear loci, revealed the presence of molecular diagnostic sites which, in addition to the aforementioned morphological character states, further support the taxonomic description as well as future integrative taxonomy studies in Mexican Crassulaceae.