John Lindley published Epidendrum subg. Spathium of the Orchidaceae. According to Lindley's diagnosis,[1] the E. subg. Spathium is recognizable by is sympodial habit with individual stems being slender (without any tendency to form pseudobulbs) and covered by the bases of the distichous leaves, by the lip of the flower being adnate to the column to its apex, and by the inflorescence emerging from at least one spathe, similar to nearly all members of the genus Cattleya as understood in the year 2000 (sensu MM). Reichenbach recognized 52 species in this subgenus,[2] of which Kew[3] accepts 48 (page numbers refer to Reichenbach 1861):
In 2005, Hágsater & Soto[5] designated the species Epidendrum adenoglossum as the lectotype of Epidendrum subgenus Spathium.