Psychotria avia Standi. & Steyerm., Field Mus. Publ. Bot. 28(3): 596. 1953.
Comparison of the type specimen of Psychotria avia (Steyermark 58056) with Rudgea duidae (Standi.) Steyerm. and R. stipulacea (DC.) Steyerm. indicates without doubt that the three taxa are congeneric, as evidenced by the elongated axillary inflorescence and persistent, terminal, costate stipule. Although the original description of Psychotria avia stated that the plant was glabrous, it was not noted then that the midrib, lateral nerves, and veinlets on the lower side of the leaf blades are minutely puberulent, thus distinguishing this taxon from both Rudgea duidae and R. stipulacea. In other respects Psychotria avia appears intermediate between R. duidae and R. stipulacea. Its winged peduncle has the width of R. stipulacea but is puberulent, as in R. duidae. Its flowers are sessile, as in R. stipulacea, but the calyx lobes are more deeply cut, as in R. duidae. The length of the primary branches of the inflorescence in anthesis is 30 mm in Psychotria avia, thus simulating those of R. duidae, but the corolla is more puberulent externally than in either R. duidae or R. stipulacea. The calyx lobes are larger, more deeply cut, and more abundantly ciliate than in the other two species. The leaf size and tertiary venation on the lower side of the leaves resembles that of R. stipulacea rather than of R. duidae. The stipules are more rounded at the apex than in either of the other two species.
Rudgea avia may be intercalated in the key to Rudgea [Mem. N. Y. Bot. Gard.