This species is characterized by its generally slender habit, axillary usually cymose inflorescences with several quite small heads of flowers, and purple-black fruits. It is commonly collected in its range, and a common species in the edges of seasonal gallery forest there. Appunia tenuiflora is morphologically rather variable; see Taylor et al. (2004: 658-659) for a discussion and illustration.  As noted there, Appunia surinamensis may not be distinct and the range of Appunia tenuiflora may extend into that region. Appunia venezuelensis is also similar to Appunia tenuiflora; these were separated by Steyermark based on the presence in Appunia tenuiflora of appendices on the anthers, vs. anthers that are unappendaged in Appunia venezuelensis.