A taxonomic revision of Mayodendron Kurz (Bignoniaceae) in Thailand is presented. One species, Mayodendron igneum (Kurz) Kurz, is enumerated with updated morphological description, morphological differences with the related species and illustrations, together with notes on distributions, a distribution map, habitats and ecology, phenology, conservation assessments, etymology, vernacular names, uses and specimens examined. The specimen Brandis 1357 at HBG [HBG522936] is lectotypified here for M. igneum. This species has a conservation status of Least Concern (LC). The leaflet laminas and wood anatomy and pollen morphology of this species are also reported in this study. M. igneum has bifacial leaflets, cyclocytic stomata, prismatic crystals in parenchyma around the vascular tissue and epidermal cells on both leaflet surfaces and its wood has diffuse-porous, biseriate, sometimes uniseriate, triseriate, tetraseriate heterocellular rays or uniseriate homocellular rays, with the procumbent cells up to 30 cells long. M. igneum has prolate-spheroidal or subprolate pollen shapes, small to medium sized, 19–25 µm in polar axis, 18–23 µm in equatorial axis, heterobrocate exine sculpturing. The pollen aperture patterns are classified as 4 types: typical tricolpate, 3-syncolpate with oblique colpi, 4-syncolpate and 6-pantocolpate.