Tyleria phelpsiana habitally, because of similar leaf character and tree form, much resembles T. floribunda of Cerro Duida. In form of inflorescence and flowers it most resembles T. spathulatus of Cerro Duida, adjacent Huachamacari, and more remote Cerro Parú. In common with both, T. phelpsiana lacks the conspicuous foliar aristae of the Cerro Neblina assemblage, and in this negative character thus further stands with the Duida assemblage. A genetic analysis of the species of Tyleria would be most instructive.
Tyleria phelpsiana and the following T. Silvana may be fitted into our earlier key (Mem. N. Y. Bot. Gard. 10(4): 9-10. 1961) between T. spathulata and T. pendula.