Calycogonium pseudofloribundum of the Melastomataceae tribe Miconieae, from eastern Cuba, a species new to science, is described and illustrated. C. pseudofloribundum is closely related to C. floribundum, with which it has been confused for a long time. It can be distinguished from the latter species by leaf features (the ovate to lanceolate leaves have an acute to apiculate apex, the blade is flat to slightly revolute, the margin usually obscurely to minutely dentate towards the apex, the adaxial surface is flat and usually opaque to whitish in dry material by presence of wax layers; they have two, rarely one, pair of secondary veins, the second pair originating 2–9 mm above the base), the external calyx teeth being 5–6 mm long, and the petals being white, obtuse to acute, 4-5 × 2-2.5 mm. An amended description and an illustration for C. floribundum is also provided.