Monographs Details: Sipaneopsis pacimoniensis Steyerm.
Authority: Maguire, Bassett. 1967. The botany of the Guayana Highland--Part VII. Mem. New York Bot. Gard. 17: 1-439.
Family:Rubiaceae
Description:Species Description - Caules 10-11 cm alti dense adpresso-canescentes; stipulis triangularibus 2.53 mm longis dense strigosis; foliis brevipetiolatis, petiolis 1-2 mm longis dense strigillosis; laminis elliptico-oblongis apice subacutis basi obtusis vel subacutis 1.5-3 cm longis 0.7-1.2 cm latis supra glabris nisi costa media strigillosa subtus costa media atque nervis lateralibus dense strigillosis praeterea superficie modice strigillosa, nervis lateralibus utroque latere 3-5 adscendentibus; inflorescentia terminali cymosa 2-3-flora; pedunculo 1-1.5 cm longo canescenti; bracteis sub floribus lineari-lanceolatis acuminatis 3-4 mm longis extus hispidulis; calyce hypanthioque 4 mm longo, hypanthio subturbinato 1.5 mm longo 1.5 mm lato extus dense hispidulo; calycis lobis quinque lanceolatis acutis paullo inaequalibus 1.7-2 mm longis 0.7 mm latis extus canescenti-strigosis intus glabris, inter lobos in sinu glandula solitaria 0.1-0.2 mm longa interposita; corollis hypocrateriformibus 26 mm longis, tubo 17 mm longo basi 0.7 mm lato fauce 2.5 mm lato extus cano-sericeo vel canescenti-strigoso prope faucem magis dense pubescenti intus parte basilari 3.5 mm glabro deinde superne puberuli, fauce intus appendicibus quinque incrassatis pilis albidis densis erectis barbatis circum pilos breviores luteos munita, lobis quinque obovatis apice abrupte mucronatis 8-9.5 mm longis 4.5-5 mm latis extus adpresso-strigillosis intus glabris marginibus ciliolatis; staminibus ad faucem tubi corollae inclusis, antheris linearibus apice apiculatis basi rotundatis 1.8mm longis; filamentis 3 mm longis papillatis infra faucem 4 mm affixis; stylo 11.5 mm longo glabro.

Distribution and Ecology - VENEZUELA. Amazonas: infrequent in savanna on right bank of Rio Paci-moni, 50 km above mouth, alt 100-140 m, 7 Feb 1954, B. Maguire, J. Wurdack & G. Bunting 37570 (holotype NY).

Discussion:

This species differs from S. foldatsii in the dwarf stems, shorter internodes, shorter leaves, much larger corolla-lobes, glabrous interior of corolla-lobes, and fewer lateral nerves of the leaf-blades.