Catasetum × grasineideae (Orchidaceae: Catasetinae), a new nothospecies from Brazilian Amazon and taxonomic notes for the genus Author Krahl, Dayse Raiane Passos 0000-0003-2899-9453 Universidade Federal do Amapá, Programa de Pós-Graduação em Biodiversidade e Biotecnologia da Rede BIONORTE, Rodovia Josmar Chaves Pinto, Km 2, Jardim Marco Zero, 68903 - 419, Macapá, AP, Brazil. & dayseraiane @ hotmail. com; https: // orcid. org / 0000 - 0003 - 2899 - 9453 dayseraiane@hotmail.com Author Schmal, Philippe 0000-0003-2993-6884 Program of Forest Ecology and Management, Albert Ludwig University of Freiburg, Friedrichstr. 39, 79098, Freiburg, Germany. & ppschmal @ yahoo. com. br; https: // orcid. org / 0000 - 0003 - 2993 - 6884 ppschmal@yahoo.com.br Author Chiron, Guy 0000-0003-0971-4715 Université de Lyon 1, Herbiers, F- 69622, Villeurbanne Cedex, France. & g. r. chiron @ wanadoo. fr; https: // orcid. org / 0000 - 0003 - 0971 - 4715 g.r.chiron@wanadoo.fr Author Silva, João Batista Fernandes Da 0000-0002-1003-1041 Mineração Rio do Norte, Rua Rio Jari s / n °, 68275 - 000, Porto Trombetas, Oriximiná, PA, Brazil. & jb. bina @ gmail. com; https: // orcid. org / 0000 - 0002 - 1003 - 1041 jb.bina@gmail.com Author Krahl, Amauri Herbert 0000-0001-7862-9624 Instituto Nacional de Pesquisas da Amazônia, Programa de Pós-Graduação em Botânica, Departamento de Botânica, Av. André Araújo, 2936, Aleixo, 69060 - 001, Manaus, AM, Brazil. & amaurikrahl @ hotmail. com; https: // orcid. org / 0000 - 0001 - 7862 - 9624 amaurikrahl@hotmail.com Author Cantuária, Patrick De Castro 0000-0002-3676-7866 Instituto de Pesquisas Científicas e Tecnológicas do Estado do Amapá, Laboratório de Taxonomia Vegetal, Rodovia Juscelino Kubitschek, Km 10, 68903 - 970, Macapá, AP, Brazil. & patrickcantuaria @ gmail. com; https: // orcid. org / 0000 - 0002 - 3676 - 7866 patrickcantuaria@gmail.com text Phytotaxa 2023 2023-04-26 594 2 89 104 http://dx.doi.org/10.11646/phytotaxa.594.2.1 journal article 10.11646/phytotaxa.594.2.1 1179-3163 7891982 1. Catasetum × aripuanense Bicalho (1963: 1) (pro. sp.), nothosp. nov. ( Figure 6A–B ). Type :— BRAZIL . Mato Grosso : Aripuan ã, mata ciliar do Rio Juruena , perto da Cachoeira Dois Irm ã os, cultivada no Jardim Botânico de S ã o Paulo , 15 May 1963 , M. Mee s/n ( holotype : SP-68441, photograph!) . Taxonomic Note: —Based on controlled crossing and germination in vitro carried out by J. Fernández G. this taxon proved to be a natural hybrid between C. gladiatorium Lacerda (1998: 90) and C. rooseveltianum Hoehne (1916: 35 , t. 172). Phenotype resulting from the crossing of these species ( Figure 6A–B ) was compared to the original description given by Bicalho (1963) and the holotype deposited in herbarium SP. The same morphological features were observed. In addition, two materials deposited in SP and ESA were analyzed and, once more, the same floral morphology was observed. It is also emphasized that both parental species occur in the state of Mato Grosso , as C. × aripuanense (see Bicalho 1963 , Petini-Benelli 2022 ), which strengthens the possibility of hybridation. Catasetum × aripuanense presents an ovate lip as in C. rooseveltianum ( vs. trapezoidal in C. gladiatorium ), with at base a tripartite callosity similar to that of C. gladiatorium ( vs . absent in C. rooseltianum ) and the margins are dentate to fimbriate (a character intermediate between C. gladiatorium , that has a fimbriate margin, and C. rooseveltianum , that presents a smooth margin). Moreover, the column in C. × aripuanense presents parallel antennae as in C. gladiatorium ( vs . parallel and divaricate in C. rooseveltianum ) (see Bicalho 1963 , Petini-Benelli 2022 ). Additional specimens examined:— BRAZIL . Mato Grosso : Aripuan ã, mata ciliar do rio Juruena perto da cachoeira Dois Irm ã os, 07 august 1962 , M. Whitten 93112 (SP-175250, photograph!) ; Mato Grosso do Sul : Costa Rica , 02 january 1997 , A.P. Santo s/n (ESA-108221, photograph!) .