This species is characterized by an often robust tree habit, petiolate, medium-sized (for Simira), ovate to obovate leaves, pyramidal, multiflowered, pedunculate inflorescences, 5-merous flowers, funnelform white corollas with tubes 5--6 mm long, and subglobose to oblate woody capsules 2--4 cm in diameter. The specimens dry with a green to brown or yellowish brown color. The petioles are well developed to only a few mm long. The style is deeply divided into two arms, to more than half its length. The leaf blades are rounded to truncate or shortly cordate at the base, and notably variable in this form. The leaf blades also vary markedly in size, from small to large on fertile stems and usually relatively large on sterile stems; the size variation may be correlated with humidity in the habitat.
Simira cordifolia was one of the first species of this genus described, and this name has been applied widely to a variety of plants. In particular, specimens of Simira rubescens from the Amazon basin have been frequently misidientified as Simira cordifolia. Simira aristeguietae of northern Venezuela is similar, it differs basically in its 4-merous flowers. Simira fragrans is also remarkably similar to the other species of this genus that Rusby described, Simira fragrans of Bolivia and southern Peru.