This species is characterized by its shrub or tree habit, medium-sized obovate leaves that are shortly petiolate, rather small stipules, several- to multi-flowered inflorescences, 5-(6-)merous flowers, funnelform corollas 6-7 mm long with the lobes as long as the tube or longer, and woody capsules 2-3 cm in diameter. The leaf blades are obtuse to usually abruptly truncate to rounded at the base, and have 9-15 pairs of secondary veins with regularly developed tuft domatia. On most plants the leaves are glabrous on the lower surface, but occasional plants are densely pilosulous to hirtellous there. Barbosa & Peixoto (1989) distinguished Simira corumbensis in part by its having 17-23 pairs of secondary veins, but its holotype specimen has 15 pairs as these are counted in this survey. The flowers have been rarely collected.
These plants were misidentified in the Bolivia Catalogue (Taylor et al., 2014) as Simira pikia, but that appears to be a distinct species is found in Atlantic forest vegetation of eastern Brazil. For their distinctions, see Margalhães et al. (in prep.). Some plants included here in Simira hexandra may fall in the circumscription of, or be confusd with, Simira pilosa; the separation species may deserve re-evaluation at least as to the characters that distinguish these.