Pseudobombax millei (Standl.) A. Robyns, Bull. Jard. Bot. Etat Bruxelles 33: 69. 1963.

Carvalho-Sobrinho, Jefferson G. & Dorr, Laurence J., 2017, A new combination and taxonomic notes in Pseudobombax Dugand (Malvaceae), PhytoKeys 85, pp. 27-30 : 29

Pseudobombax millei (Standl.) A. Robyns, Bull. Jard. Bot. Etat Bruxelles 33: 69. 1963.

Basionym. Bombax millei Standl., Trop. Woods 45: 16. 1936. - Type: Ecuador. Sept 1929, L. Mille 868 (holotype: F! [F0052111F, F0052112F, JSTOR image]). = Pseudobombax guayasense A. Robyns, Bull. Jard. Bot. État Bruxelles 33(1): 68. 1963. - Type: Ecuador. Guayas: vicinity of Guayaquil, Cerro Azul, 10 Sept 1955, E. Asplund 17588 (holotype: S! [S10-39074, S10-39076, S-R-11308, JSTOR image]!; isotypes: BR [BR0000006961367, JSTOR image], NY! [NY00133609, JSTOR image]), syn. nov.

Notes.

The characters (leaflet shape, calyx dimensions, and pubescence of staminal tubes) used by Robyns (1963) to segregate Pseudobombax guayasense are not sufficient to distinguish it from P. millei based on a more comprehensive sampling of herbarium collections. Previously, phylogenetic analyses of DNA sequences were interpreted as supporting the accessions examined of these two taxa as sister groups ( Carvalho-Sobrinho et al. 2016: fig. 2), but we now consider P. guayasense to be a synonym of P. millei on the basis of combined morphological and molecular evidence.