Recently Gangopadhyay & Chakrabarty (1993, 1994) proposed the combination Archidendron clypearia (Jack) Nielsen var. montanum (Benth.) Gang. & T. Chakrab. When I compared this to some papers Nielsen wrote (1984 (et al.); 1992) it would seem that this new combination would be identical with A. clypearia var. casai (Blanco) Nielsen (1984) allegedly based on Mimosa scutifera Blanco var. casai Blanco (1837). When I looked up this basionym with its curious varietal epithet I discovered to my vast surprise that Blanco had not published this combination at all, as had already been observed by Merrill (1918). Blanco (1837, 1845, 1879) merely described an unnamed variety of Mimosa scutifera Blanco with ‘casai’ or ‘casay’ as one of its vernacular names. Fernandez-Villar (1880) cited the var. casai as a synonym under Pithecellobium montanum Benth., so the combination was not validly published there, either. Naves (1879) seems to have been responsible for the plate of Mimosa scutifera var. casai, but in its caption he also cited P. montanum Benth. var. subfalcatum Miq. (1855). I have found no instance where var. casai was validated before Nielsen et al. (1984) used the epithet. Kostermans (1954) without comment cited var. casai (‘ cassai’) in the synonymy of Abarema clypearia (Jack) Kosterm. He regarded Merrill Sp. blancoanae 461 (A, holo, BM, CAL, K, L, NY, P) as the lectotype, but as the combination was then not yet validly published it was of course only a voucher. It became a neotype when Nielsen et al. validated the combination.