Begonia xochiatencana (Begoniaceae), una nueva especie de la sección Gireoudia de Guerrero, México

Begonia xochiatencana from La Montana Region of the state of Guerrero, Mexico, is described and illustrated as a new species. It clearly belongs to Begonia sect. Gireoudia due to its prostrate, rhizomatous habit with radicant leaves, persistent, keeled stipules, staminate and pistillate flowers with 2 tepals, zygomorphic androecia with stamens whose filaments are arranged free from each other on a common receptacle, and 3-locular ovaries. It does, however, differ from the other species due to the presence of several characters that are uncommon in the section: stipules of each pair joined by a band extending from the keels, pubescence of leaves and peduncles consisting of multiseriate trichomes, subsymmetric, palmatilobed leaf blades with the texture and consistency of fabric, bristly above and pitted below, and purple, almost black bracts.