Type. Seringal San Francisco, Alto Acre, Rio Acre, Brazil, Oct 1911, E. Ule 9844.
This species is distinct in the acuminate, abruptly cuspidate stipules, pedicellate flowers, deeply lobed calyx, and mottling of the 3-lobate bracts. It is distinguished from P. microbotrys by the above characters, and in addition has the terminal stipule only persistent.
The type collection from MG has been examined and shows a deeply lobed calyx with the 3-lobed bracts mottled brown. This modifies the original description in which the calyx is described as “minute denticulatus” and the bracteoles as “lineari-lanceolatae acutae.”