Cephaelis kaieteurensis Wernh., Jour. Bot. 52: 313. 1914, not Psychotria kaieteurensis Sandw., Kew Bull. 1939: 552. 1940.
This species is closely related to the preceding, P. transiens Wernh., from which it differs in the non-ciliate, completely glabrous, obtuse to rounded bracteoles, the more numerous flowers of the central and lateral heads, which are more numerous in the inflorescence, the usually longer lowest subtending bracts of the inflorescence, the shorter calyx and hypanthium, and the more prominently caudate-acuminate apex of the leaf blade with less prominent tertiary venation. Some specimens, however, present intergradations between the two taxa. Thus, Maguire & Wurdack 33901 from Ptari-tepui shows a central ray of the inflorescence 3-pronged and 7-9-flowered, with the two lateral rays 2-4-flowered each, thus tending to the 3-pronged central head of P. appuniana, but the inner bracts or bracteoles are pointed and ciliolate around the apex as in P. transiens. Moreover, Maguire 32116 from British Guiana has the three sessile heads as in P. transiens, but the lateral head on one specimen is 8-flowered instead of 3-flowered, while the leaves with their long caudate-acuminate apices approach those of P. appuniana. However, the inner bracts or bracteoles are intermediate in their glabrity and amount of ciliolation, since the margins and apex are mainly glabrous and subacute, but on one or two of the bracteoles there is slight indication of ciliolation along the margin or near the apex.